Not sure if you have ever seen or heard about the documentary
My Name Was Bette: The Life and Death of an Alcoholic. http://www.thebettefilm.com/ Maybe show her the trailer to this movie because it sounds like the path she is leading down and could possibly serve as a wake up call to her that this is what her future looks like. Sorry for your situation. I can only imagine how devastating it is for you and your brother. Knowing how progressive the disease is only makes it all the more difficult.