I am sorry for your struggle. My Mother went through this as well but times change. I suggest listening to the works of C.S. Lewis before you decide to break. You will be the very one to keep him from deaths door.
I'm sorry but I have to disagree. HE has to be the one who wants to stay away from death's door. Most times we become the enabler for the alcoholic/addict to continue in their disease. We have to be selfish, for once, and take the necessary steps to get ourselves healthy in an emotional and mental sense.
We can't help anyone else by being an enabler/co-dependent. We are not responsible for another person's disease or recovery from it. We have to allow the alcoholics/addicts in our lives to experience the consequences of their own actions. Its the process of detachment - which can help us look at our situations realistically and objectively.