Daughter in law doesn't like Son in law

Well, usually if you leave children to bicker, they sort it out between themselves in the end.
Maybe you could try that approach, because you don't seem to have a problem with any of them.. meaning politely that its not your problem unless you choose to make it so.

Yes, thanks for that, I agree with you, if there is something 'unsaid' going on between them then they must sort it out between themselves. I feel a bit sorry for my daughter & her brother as they are the victims here, but they have choosen their partners & so must get on with it. If my son wants a relationship with his neices, he will have to make the effort to see them. I'm being used as a bit of a 'go between' here & I don't have an issue with any of them, so you're right, they must choose to communicate directly with each other or not.

I wouldn't speak to your DIL about it - you don't have a problem with any of them and you may only cause upset between DIL and you.

They really need to sort out their differences - and not at your house or involve you in any way. Why does she dislike him, I wonder?

Your DIL really should try to be civil for the sake of family harmony and for the sake of the DGD even if she dislikes her sister-in-law's husband. The DGD will notice and be asking questions before too long - children are often aware of underlying tensions.

Why would your daughter need to tell her brother and sister-in-law not to come to her birthday do? If she doesn't want them there because of the issue you mentin presumably she hasn't invited them?

As others have said, I think you have to just leave them to it. They'll either muddle through civilly enough or they won't.

Had a similar situation in our family. Left alone the two people managed a distant but civil relationship. I refused to worry about it. Thought about it in the same way as a workplace. Colleagues don’t have to be friends, just learn to work together with a shared aim, whether than be a birthday or a workplace goal, same principle applies. Hope it settles pixie, please don’t get in the middle of it,

As a family, we have never 'invited' each other to birthdays (unless it's a formal do for wider inclusion) we just visit the said person on that day, unless anyone is on holiday/living away/ made it obvious they are not going to be home (like going for a day/night out) My daughter has on this occasion told ME she doesn't want her to visit, so as above advice says, she really has to tell her that herself.

Thank you cornergran - feel better for chatting about it & agree to keeping out of it - as I said in my opening thread 'we can't all like each other' & so they must do the same as many of us have had to do in the family & at work - try & rub along together.