Hi, OP.
I have read all your posts.
I see your situation as one similar to a kind of imprisonment. I am sorry, i am not trying to be harsh. You have no support and you can not even speak with him about this issues. You are stuck.
You say he doesn't remember what it was like when he is at his worse and he can not understand how it affects you. As he has lost that ability, then he CANNOT be the one calling the shots on you manage this huge change in your lives. He has MH illness, you do not.
In MH illness, the person always and only does what is comfortable for them. And this does not lead to healing and recovery.
At the moment, he has created a little bubble which he refuses to step outside off. That bubble is only possible because you and the kids are there providing him with company, food, clean home, shopping, interacting with the outside world on his behalf so he is not going to get better.
And his mental health team are not going to push him because he is being looked after. Imagine if he didn't have you (& DC) as a resource, his team will be more active in getting him out of this bubble.
I am not saying you should leave him, it's clear you do not want too or feel you can. I can't help but think the current situation is assisting in (i hate to use this word) enabling him in continuing in his current mode. So something has to give.
For him, maybe a different approach, e.g you start stepping back a little, you (&DC) can start seeking some respite time away from him (he goes away or you & DC go away).
For you, start seeking support for yourself, talking to close friends etc you will see how different and better you feel. Don't stay in this limited/restricted living he has imposed upon you (and DC).
Also, maybe hearing from (or seeing his friend) may trigger him to start trying outside his comfort zone since he doesn't want people to see him as one with MH challenges. Obviously, this or other similar strategies tbd with his mental health team.
He has to try. If he wants his family.
You have to try. Try something for yourself.
He can't live like that forever. YOU CAN'T LIVE LIKE THAT FOREVER.
Welldone on being such a supportive partner and coping with the kids, your partner and with life.