Maude, I am so sorry that the merry go round has started up for you, again. Al anon has been helpful to me but to be honest it is because I am working at it going to several meetings a week. It is worth the effort. I know it is hard with a child but in addition to physical meetings there are phone in meetings virtually all the time. Google "al anon phone meeting" there are different numbers for different hours of the day.
My gem from last nights meeting is that being angry is like injesting poison and hoping your AH gets sick. Your anger is not a match for his addiction. Feeling powerless feeds your anger but if you can manage to detach you will be doing yourself a favor. His guilt, his seeing you be happy without him, being able to do things that drunk people cant do, those are the things that might beat his addiction. It has to come from him.
Go out with family and friends leave him home with his bottle(s). It is the best thing for you and your DS and that is all you can control. You can't change him, he can change him, let him.
Good luck and read through the posts here.