Jumping in here.
Silvers, I understand not wanting your parents to spend their last days in a nursing home. I had that struggle as well, for different reasons. I finally placed my mother because caring for her was killing me. Nursing facilities are all different, take time to find one that suits them best. A good facility will not allow your parents to sit around all day watching TV and bemoaning what's wrong with the world. My mother was very active, participating in nearly all the activities available to her, in spite of declining health. And............this may sound cold, it is a natural consequence to choosing to continue on the path of alcoholism. I am a recovering alcoholic.........I would have said or done anything while drinking to get others off my back. Mr. your mother's empty promises may be nothing more, but it's possible she wants to stop, but can't. I would get her help, if she takes it great, if not she has made the choices. The only option I see to protecting them (and you)from themselves if they won't stop drinking is long term care. So what if it takes all their money, so be it. Remember it was their choice to get to this point.
I might add I stopped drinking through AA. No one intervened, no treatment, just sick and tired of the life I was living.