I’m ashamed of my son’s behaviour

I think OP needs to find out what the abandoned family wishes to do once they have recovered a bit from the obvious shock. If they wish to return to UK and to the home they left, which sounds like that may be in their best interests as at least state schooling will be free, employment might be easier to find, and/ or access to housing benefits if the home is not available, then try to assist if possible.
I don't think you should get over - involved with your son or for finding solutions, but your son ought to be able to provide you with an explanation and to say what he intends to do by way of support for his child. His partner, if they are not married, isn't not entitled to support for herself, but hopefully will be able to contact child support agency for a child maintenance sum if adult son does not make suitable arrangements voluntarily.

Gosb. My first instincts would be to remind you you are 80 and your self care is paramount.
I would be honest and say i am so sorry your in this situation but there is not much you can do as you are a pensioner.
Then have a nice glass of red and write down what is within your capabilities.
She will be able to claim benefits and will have parents.
A big note to say out loud is

This is not my fault xx

Just be a listening ear to both sides. Trying not to appear to take sides as it could all go horribly wrong.

I would be inclined to remain supportive of both parties initially. Not financially though. What country are you in? Have you heard his side of the story? Is his business in trouble? Why has he changed his mind? There may be a genuine reason and he is still your son. In the longer term I would stick with giving generous birthday/Christmas gifts to your grandson.

What a dreadful situation. I am so sorry. I do not think you are responsible for your son’s actions though I can understand that you feel ashamed of what he seems to be doing. A sympathetic ear will be helpful to your daughter in law in these circumstances. I am sure she is distraught whatever the rights and wrongs between them. You are not empowered to sort out this mess unfortunately and shouldn’t try to take that on in your mind or feel you can or ought to sort out something that you actually can’t. I think taking a little time to see how things develop as some people have suggested is good advice. If your son is likely to be abusive if you confront him, I think it’s OK to avoid that, in the meantime anyway. Financial help may seem like something you can practically do but I wouldn’t leap into anything without a lot of thought unless it’s a little emergency funding. Take care of yourself too. Self soothing is always helpful. You are also distressed and in shock. Also feeling angry. Which is an exhausting emotion. If you son does have atypical personality traits that could help you understand and perhaps cope better with how he behaves. I think by the age of eighty we need to take things as easy as we can. Things will come to pass one way or another. Good luck and my blessings.

It does strike me that moving a business from the UK to another EU country at the moment might be a bit of a nightmare. Perhaps your son was carried away by the whole idea and only really appreciated how difficult things would be when the crunch came. None of us know what goes on in or children's relationships or even sometimes in their lives. You shouldn't feel responsible. Nor I think should you interfere. If you can easily help financially then that would be kind, but you impoverishing yourself won't help. I hope things get resolved and you get some peace of mind. It is extraordinary isn't it that our grown up children can cause more upset than they ever did when they were little? Good luck!

I see you're all not in uk so its hard for us who are to give much advice, we don't know what help or support there is in your country, especially financially- or the laws, regarding breakdown of partnerships etc.But i would suggest first and foremost she sees a lawyer to ascertain how she stands on getting your son to support his son financially- and also about how she stands legally as regards to this lease she's in effect been coerced into signing for- believing she was going to do so as a 'representative' of your son.If she can get out of this lease early could they either- return to uk and so get more help financially and legally that she will need, or stake a claim on their old home(is your son still living there?or what?)or if she wants to stay where they have moved to is there any help she can get? Or a job she could take? She really needs legal advice first& foremost.Perhaps it would best you pay for that for her if you can afford to, rather than towards her rent- then she can take it from there.Also another idea would be to move in with you, if you have the room, providing she can get out of the lease she signed, would that be an option? Or does she have any other family either there or in UK?Either way i think she must see a lawyer anyway as she's been coerced into all of this- if it was me i would tell my son my opinion of him & what hes done, regardless of if he sent me 'vile insults' back.(in fact id send him a few in first place& see how he likes it) I think you may have 'allowed' him to get away with a lot in the past & so he feels 'entitled' to be this way.Maybe his partner has too? He seems spoiled.He has calculated all this i doubt its a last minute thing.She definately needs legal advice first.

I really feel for you. One person here recommended taking your rose coloured spectacles off. I would agree with that. In the end reality is best.

Look after yourself.

Not your call. If you feel financial hardship may be experienced you could always offer some assistance based on helping your GS.

Why has your son made this decision? Has he actually given any reasons?

I feel for you Red, as I am struggling with my own daughter, who is high achieving. Will look up the disorder. I also feel the GC is the main priority in all this. I know you will be there for the child. The DIL will find her feet, but having moved she prob hasnt the contacts for work and earning a wage yet. It will all pan out in the end

You have no moral obligation to support your son, his wife, or their son.

Any financial help you want to give them is another matter, but if I were you, I would keep my purse tightly closed right now.

If your daughter-in-law has confided in you, by all means continue to be in touch with her. Tell her, as you have said here that you do not know what is going on in your son's head right now, but his behaviour is making you feel ashamed.

She needs to demand a straight answer as to whether your son wants her to move back to him in the UK, or not. It is her marriage and she needs to decide whether she will continue it or not.

I am sorry you are so worried, I would be too, but your son and his wife are adults and need to sort this out themselves.

The child has as always when parents disagree no say in the matter, but there is nothing you can do about that right now.

STAND WELL BACK and stay out of it. As others have said, you don't know what's going on behind the scenes. Giving them money may just make things worse (it will look as though you're taking sides, and a lack of money may force them into resolving the situation more quickly). They could be okay in a few weeks but anything you've said or done, in the meantime, will be remembered far into the future ...

Hard to do but I'd do as LuckyoldBeethoven suggests and sit on your hands for a while and let the dust settle. If you step in too quickly, and things blow over or your son steps up to the mark, you run the risk of interfering. Think it's a waiting game for a little while hard as that is to do sometimes.

Red I’m very sorry you have all this to face.
But I agree with Jane10, you need to hear your son’s side of things before jumping to conclusions or rushing to judgement.
If you phoned him or emailed him, and simply said ‘I’ve heard from X that you're not coming after all, is that right?’ and waited for an answer before commenting, he would have no reason to be nasty or abusive in response. You might even find he confides in you and you could be a support to both of them.
You do have my sympathy

Without knowing the ins and outs it’s very difficult to have an opinion.
Only one I would take, regardless, is what a dreadful thing to do to a 6 year old boy.
I would help as much as I realistically could, for his sake alone.

Sorry suggested

Thanks for all your helpful comments. It has been suddested that he might have « high achieving borderline personality disorder» He demonstrates a lot of the symptoms.
It would explain a lot and makes me less angry.

Surely, both of them would have signed the contracts for the rental home and school fees so both are responsible for paying. If she signed them just in her name, she should have suspected something was a bit fishy.

I think it’s a case of letting any dust settle, and just waiting to see how you could possibly help. Others are right to say to hold back. They are not your responsibility. I know it’s hard, but you have your own well being to think of. If you interfered, it could set them back, and then you could be blamed. Take care.

Personally I would feel responsible for ensuring the well being of the mother and child. I would say something like" I don't have enough money to support you, and I really think that is my son's job, but I will make sure you are housed and fed while you get on your feet without him".
I am not saying that is right for you, just offering a point of view.

Luckygirl, snap. A friend of mine had the same thing. Except they had relocated to Japan. He left her with very little money and air tickets for herself and the children to get home to her parents while he set up house with a women he had moved to Japan to be with.

My friend had given up university and potential careers to support him in his career while following him around the world.

She is one of the reasons I have been such an ardant career woman. I refused to be left alone and poor, with children.

I suppose I go for the equivocal and 'couldn't disagree more' is pretty strong and not how I would express disagreeing with someone in a situation which was far from clear.
Of course it doesn't break guidelines, perhaps I'm too mild. Thank you for your intervention Lucca, let's hope the OP finds all comments useful.

We always feel responsible for our children's behaviour whatever age they are, strange but true. I would hold fire for a while RedDevil3 and see what transpires.
Support your son's partner and grandson emotionally at the moment but not financially. It must be upsetting for you to think your son can behave like this but as everyone else said he is an adult and must face up to his responsibilities.

Something similar happened to a friend of mine - she and her OH moved home as he was changing career - they chose a new home together and immediately after they moved in he upped and left for someone else, leaving her and the 2 children in a home that she might not have chosen if she had known what the true plan was. He knew exactly what he was planning to do - it was a calculated act of treachery.

OP - your son must sort out his own mess; and you should tell him this. It sounds as though he has "form" and you should not enable this repeat behaviour by picking up his responsibilities. I do see how hard it is for you; but he needs to realise that he must take the consequences of his own actions and cannot look to you to bail everyone out.