Wife cannot tolerate my adult children, can't invite them for Christmas.

You don't specify what the dangerous illness is, just allude to MH problems with B.. So a lot would depend on the history and how the illness is being currently managed..
I would not give keys to either of them, but I would probably let C stay in the house..

I think your paramount concern should be your wife's safety but in order to maintain a relationship with your children try to establish how well they are before agreeing to allow C to stay.. and meet B somewhere else to exchange presents.. If this goes well perhaps he could visit just for a meal with you all.. It will depend how you assess his health on the day..

I am sorry for the ex-wife who has to cope full time with a difficult son.

Don't be so damn rude.

Also, if "his kids" haven't been invited around for n xmases where n is a large positive integer, why is it suddenly a big deal?

Exactly. WE DON'T KNOW. So how about refraining from judgment?

People have made helpful suggestions.

Whatever happens, I hope the OP will come back and tell us what does happen.

Perhaps.
Perhaps not.

Please give "perhaps" all its meaning.

We do not know the details. as people keep saying.

I see.

It doesn't to me. It sounds as if she's afraid she'll be attacked because of things in the past. A husband should understand that. He doesn't have to like it but he should understand and act accordingly. Perhaps she only has to "keep reminding" him because he's being obtuse about it.

my wife constantly reminds me that my children should have more exact plans and stay with my Ex as she has always had first dibs on who they see at Christmas.

Sounds quite dictatorial to me.

In direct response to the OP, although I think "empathy" is over-rated and pftenused as a kind of weapon, I do think you could pull out the stops and try to empathise with your wife's understnadable fears.

So why was your "would not allowdictating" post necessary?

Yes, I've already said that.

The OP's wife is not dictating anything MissA. She is expressing her fears because of background that her husband knows about.

He can see his kids, especially the 'problematic' one, somewhere out of the house, can't he?

There is no way I would allow a partner to dictate that I wasn't "allowed" to see my children.

If it could be done safely, then see them I would.

Was the childs mental health in crisis at the time of the incident?

Is it better controlled now?

You should support your wife in this. The possibility that B may be able to get a key for her house (and yours obviously) would fill me with dread if I was in the same situation. She is a survivor of SA as you have mentioned, we don’t know the ins and outs of everything here but on the surface, if she is having bad dreams about the situation then no! You say she is usually loving and supportive - then with this situation, you should be the same to her.

Yes they are your children but they (or one) have done bad things from what I have understood. She should come first.

This is how l read it MercuryQueen,

If your wife is having nightmares about your son and you admit he’s been dangerous in the past, I don’t see how a compromise is possible. Your wife deserves to feel safe in her own home.

This doesn’t sound like a personality conflict, but a genuine safety concern.

Can I just clarify one question?
Does your wife have a valid reason to be fearful of your children or one child in particular or is she just a very nervous person?
I think the whole problem hinges on that question
If the answer is yes then have your child/children round when she is not there or meet outside the house If the answer is no then a gentle talk or some outside help for anxiety is the best route

This is complicated your conversation should be with your wife before going public.

I think if the poster was a woman we wouldn't say put your husband first, Shelflife

There are some safety issues which we don't yet understand - and there's not much time now to get professional support before Christmas.

I have no solution but I wouldn't like to cut off my children - and the one with the "problems" doesn't need to stay.

Can their sibling help with them in any way? I take it your children are adults.

If your wife is afraid of your son you must respect that. Is it possible to meet up outside your home , a cafe or restaurant? Has your wife good reason to be afraid? - if so then you must put your wife first.

There must be a workable way around this situation.

If I were you, I would decide on one, and present it to your wife, with no room for manoeuvre, as long as she is safe.

Could she go and visit her children for a few hours, or could you take yours out to eat?

It's difficult to assess, since we don't know if she has actually been in a dangerous situation, caused by your child, or feel that she would be.

How do you honestly feel about your troubled child?
Are you afraid of them?

First of all there aren’t enough grandads post on here so well done you and welcome
Of course your children should visit but is there a genuine reason your wife is afraid of the middle son ? You say he has a dangerous illness do you mean danger to himself or others? could he visit when she is out if he’s really that bad? then you could have an hour to yourselves and every body would be happy or could you invite him for a meal or even just a coffee outside the home
There are some voluntary counselling services around

It seems you don't like confrontation to the extent you'd rather let your family do as they please at the expense of your wife's wishes, and in fact her mental and possible physical wellbeing. . If l had good reason to be scared of my partner's son and my partner intended to put me in a potentially dangerous situation with his son l would probably end the relationship.