Oh, I have no clue. But, it doesn't matter too much, because there are no actions to take... finally.
I told him the school wants me to get professional counseling for our son, and my XH is suddenly supportive of it. When we were together he was totally against any kind of counseling for us, or any kind of intervention at school for our son. It wasn't until the divorce was nearly finalized and we both had moved across the country, that XH said he wished he hadn't scoffed at counseling.
So now I think the reality of losing his family has hit him and he's suddenly reconsidering his attitudes. He's asking for old photos of our trips and talking about shared memories and being cooperative about getting help for our son. But, I have no clue if he's taking steps to deal with his problems. And I guess I don't know what that would look like for him beyond counseling, an AA program and maybe a doctor for his insomnia.
I don't think I have to answer any questions right now, or any time soon. I'm not about to uproot my son again, even if XH said he wanted to get back together. He'd have to come to us. And that won't be an option for him for a few years. Maybe by then I'll have moved on. Certainly he'll have had opportunities to do the same.
If XH said he wanted to move here to be closer to his son and approached me about trying again, I'd know something major had changed because that would be totally out of character for him. But if he decided to take that kind of initiative and risk for what he wanted, and I didn't have someone else, that would be great. So whatever happens, the problem solves itself. And for now, I guess I'll just enjoy knowing that, in fact, letting me go is cause for regret.