I have been exactly where you are at. I found that I had to detach. Bounderies are always in place with me, it isn't easy, you have to be aware at all times.
The depression is from not feeling loved and needed, I had to find new interest's and really get into the things I enjoy doing.
My ex husband of 18 years was/is alcoholic and then I dated a recovering alcoholic for nearly a year.
Alcohlics are selfish people, drinking or not drinking, they tend to find other things to get addicted to and for people like us (co-dependants) it is not healthy for us to be in relationships with them.
YOU are the important one, not him.
Try to not let the depression overwhelm you, realize that you must accept him for the way he is and move on with your life. I suffer from depression as well, and I am currently on Prozac, it helps fight the urge that I have for wanting to always "fix" things.
Please don't assume that if he gets into the program that he will "work" it. Do not expect him to amend to you, he may not. Be careful of expectations, they will always get us in trouble.
Keep reading and learning. I am here if you would like to talk.