Mopsey, I'm sorry to hear that you are a bit frustrated about the situation between your son and your h, but it's something you can't fix. This is something that those two "boys" will need to fix all on their own. You have to remember that when they are this messed up, they generally choose one child to be close to and the other child is left on the outside of the inner circle. This is what happened in your situation. Also, your son has made it quite clear to your h how he feels about his father's behavior. Until your h feels safe w/your son and your son isn't showing the anger and has also let it go, your h will keep his distance from his son. You have to people pulling at the opposite ends of the rope. Someone is going to have to give and it's going to be on their terms and in their own time.
I'm sorry about this situation. I know it's very difficult to endure, but you have to find a way to just go on w/your life and do the things you need to do in order to stay sane. They will either reconnect or they won't at some point. There's nothing you can do and that's the sad part in all of this--it didn't have to happen this way.
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.