Maybe the space will do all of you well. I know he is going through a lot of changes with his new found sobriety, but I don't think it's fair that you and your son are the ones to leave. Maybe it's the best arrangement for all of you regarding space, but I still don't think it's right.
Good Luck to you and your family. I know this is going to be a tough time away. But maybe your absence will make him realize what is so special about you that you stuck it out with him after all of these years.