Ds won't talk to me

Step back for your own sanity too.
What's meant to be will be.

Excellent post from @LoremIpsumCici and I don't have further advice to add.

Only to say I'm so sorry you've all been through such a terrible time and I hope you also have ongoing mh support?

You may want to look at young carers support services in your area, your local council offices should be able to help put you in touch if such a service exists in your area. I think both your children would qualify (some young carers services will support young adults too) and it could be another helpful form of support for both of them.

Yes, the 18-25 service will have family work professionals but will be lead by son as to whether they’ll offer it or not. Hopefully he’ll agree.

Sorry to be so blunt but, that rando from the hospital who you say children’s services were so keen to look after your kids, did he……do something to your son? Have you ever asked him that?

Can you ask CAHMS for family therapy? It sounds like it will be a slow burner, but be consistent with your approach to him, and let him know you’re willing to talk about it all, as hard as it is, when he’s ready.

Fwiw, I think both of your DC would benefit from you getting some support for yourself to enable you to improve your own self esteem and to feel stronger emotionally without relying on other people's validation and appreciation to indicate whether you've done enough.

Your posts are focused on other people, their feelings, what would be best for them, how you can help them, how you can support them, how you can give your time, home, resources, effort, love to them, and I suspect that in doing so, you hope they'll return your efforts in the way of appreciation, acceptance, support, validation, approval, which fulfils your needs and makes you feel valued.
It reads like you often don't feel like you're doing enough, and you're almost obsessively thinking of what more you can do in order to meet everyone's needs, so they would show appreciation for your efforts to make a difference and fix peoples problems and in turn, that would make you feel valued.
I wonder how often you invest the same thoughts, help, support, time, resources, effort and love into yourself. I suspect you have long been in a habit of sacrificing your own needs in favour of other people's, with the hope that they will reciprocate somehow and therefore meet your needs.
Your DS isn't in a position to meet your needs, as I'm sure you're only too aware of, but you can build yourself up and by doing so, you can have an enormous impact on the mental well being of the people you are trying to help, by being a stronger happier version of yourself.

Absolutely this, if you've been i hospital for 3 years, apart from weekend passes... its been a horrible time for your dc.
The weekend passes weren't to allow you to parent were they really? They were about what was best for you and your needs?

That poor kid. And nearly 18 or not, he’s still just a boy. Can the CAMHs worker do anything to get him more intensive therapy or social services involvement so he can stay elsewhere that’s safe if he won’t come home to you? He badly needs help and if he’s this angry with you you’re not the person to do that.

The trauma he (and his younger sister) have gone through would be a lot for an adult to deal with, let alone a child. I don’t know what your daughter’s mental health is like but given everything she has endured as well I’d want to line up some kind of help for her to process everything before it gets as bad as it has for your poor son.

You are not what he needs right now. Who does he like and get on with that can keep him safe - can he stay with your brother on a longer term basis while he gets the support he needs?

At the risk of being completely flamed, you come across as though you spend a lot of time thinking of others, organising for other people to get what they need, fixing other people's problems but if you are honest with yourself, does that come from a place of strength on your part, or is it a role you have carved out for yourself because you need to feel valued?
I say this after reading your posts about the unhealthy relationships you have had, and how you look to other people to 'save' you, for want of a better phrase.
Now you need to fix things with DS in order for you to feel better. It reads like a lot of your emotional well being rides on how other people, including your DS values you as a person, and for someone with poor mental health, this can be a heavy load.

Would you say you are emotionally strong? Do you find yourself overstretching yourself to accommodate people? Do you feel you are valued? Appreciated?

You are considering moving out of your own home and moving your DS's father into your house, the same man who has had severe mental health problems which contributed to you having a breakdown because you think this is what your DS needs or would prefer, but surely if your DS returns home, the deal is that you also live there and he is free to make the choice as to whether he wants to stay under the same roof as you or not?

I mean this in the kindest possible way, but I think you would really benefit from examining your feelings and building yourself up to a place where you feel emotionally strong enough to value yourself, without having to accommodate other people, simply to feel OK.

I didn't actually have the opportunity to focus only of me because I had to keep things running at home

I was referring to the 3years you were in hospital and your DS was being raised by his Dad.

Unfortunately you are seeing this from your point of view saying how hard you've tried but it doesn't erase what happened.

He's deeply traumatised by it. He needs to deal with that on his own terms. He clearly regards you as a negative force and part of his life.

He is allowed to feel like this. You can't undo what's done.

It's harsh but that's the reality. The most you can do is recognise this, respect this and say that you will be there in future and hope he eventually comes round. You can't force him to stay in touch.

Worse still if you push him, even if he's vulnerable, you could make everything worse.

He needs the support of others in his life if he's vulnerable. You can't be that support person because of your history.

You can't fix any of this. It's awful and it's desperately sad that's the way it is.

Make sure others know this. Make sure they know you are worried about him. But back off. You don't have a choice. This isn't about your feelings and how much it's breaking your heart. This is about him.