Sonni, Your h could very well be entering the "withdrawal" stage. If you have read about depression, there comes a point where they will withdraw from just about everyone and everything. Because he's close to his son, he may continue to see him. You h isn't doing anything backwards....he's doing exactly what he's doing for a reason and his stages are just intermixed right now.
I would accept him for who he is right now...if he comes over, fine; if he wants to help out around the house, fine. Don't set yourself up for disappointment. Always keep your expectations at zero and that way you are not hurt or disappointed. As for getting together to discuss a divorce or where the relationship is going, I seriously doubt that he'll come around for that discussion any time soon. It's very evident he doesn't want to talk about it right now. That's why it is important that you decide what you want, do you want to continue to stand or have you had enough? Only you can answer that question. His journey cannot be rushed and he's a slow mover, but at least w/him doing it slowly, maybe he'll grow up in the process and not repeat this cycle down the road and can finally face all of his issues and resolve them.
You have to decide what is best for you and your family.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
