I'm going to say, don't bother with him. Go with what your body and brain us telling you.
It well end up causing difficulty and misery your routines will be upset your DCs will be confused and questioning and ask yourself;
how will I benefit from this, how will MY life be better.
I know there are loads if people who will witter on that there must be contact, but they are not in your situation.
Was he a consistent person before he upped and disappeared? Is there any way he can confirm that he has changed for the better, like his go writing you a letter saying he'd done the MH assessments, he takes his meds, he has regular blood tests and checks, he's done his therapy. It us he just expecting you to take his word.
How much has he done to show you that he's now a better man? Is he being proactive in telling you stuff or do you have to eak it out of him?
Overall ask yourself, will my life (and by extension the DC's) life be better for all this?
Is a hard hard job being a lone parent to four under the age of 10, I only have two who are 10 & 13. so I'm going to vote don't make your life harder.