Sounds like it's a very complicated situation. I think it's honorable to help him but you're realizing yourself - where do you draw the line? Is there an in-treatment facility like AAA he could go to? From your perspective you need to ask yourself - why do you do this and how long can you do this for? Is there a co-dependency thing happening? Is it interfering with your own mental well being? It's find to help someone as long as you're not hurting yourself in the process. I wish you peace and I hope your friend gets well.