I must admit, most of the advice I give here is to FuckThatGuy and forget him! But I can see you need a different kind of support, and I wish I could think of some good advice..
You're right that him being scared to be alone is not your problem. Given he could still have behavior issues, including being violent fairly recently, I do worry about your kids being around this.
I will admit too that I'm pretty angry at my ex and think he's a terrible father and example for our children, so we have that different too given you think your WH has still been a good dad (that's great!). But I think it's the same that we should be protecting our kids and teaching them the difference between acceptable behavior and NOT acceptable behavior.
Are you wishing to separate? And does that mean he needs to get his own place or you will be moving? Whatever YOUR wishes are, I would start being firm about your boundaries.
My ex lost pretty much ALL of his friends and family after D-Day, and even my ex-MIL goes through me to see the kids cause she can't stand dealing with him. But I don't worry about his support system at all. His actions, his consequences.
But given your WH might need continued medical care, perhaps your feeling the need to at least support him in figuring out how to accomplish this on his own? Whatever he is leaning on you for, I would start telling him he needs to lean on someone else. I would start limiting your contact with him and let him get his life straightened out for himself..
There are so many levels of co-dependency, and anyone can fall anywhere on the scale depending on the situation and players involved. You have given so much to this guy, and I'm just hearing that you need to focus on yourself, so whatever you can do to get him going to other people for most of his issues, that would be my advice.
I can't imagine the anger and pity you must feel at the same time for him. And even resentment. And resentment to even "God" or the "universe" about all that has happened to you. It's really not fair what some people have to go through, and you've been amazing keeping it together. You deserve a break, and I'll keep sending prayers for you..