So Tired, I'm in the same boat as you are. My XABF is committing alcohol suicide as well, and will eliminate anyone from his life who mentions rehab. He is a Florida resident and three of us are about a week away from filing papers to have him involuntarily taken in for asssessment then treatment. It has been a 10 month journey for me trying to FIND two others who would sign. All his ex-friends and family have washed their hands of him, or are resigned to him dying. He has done such evil acts to some that they are looking forward to the day he dies.
Anyway, PLEASE make sure there are no similar laws in California as those in other states. It is worth a try, at least. If he is bound & determined to kill himself, he will. Like you, I could not stand by and watch R kill himself. It would have killed me too. After I lost contact with him, an XGF moved back in. She got a ring on her finger, and the word on the street is that she'll watch him drown and inherit the $2 mill. That's blood money, I say.
You say "I find him a disgusting, self-absorbed 8-year-old when he drinks." Truer words, m'dear, truer words. It is a filthy, disgusting world in which these alcoholics live.