I have had more exposure to this disease than I'd wish on anyone...I, like you, grew up in its shadow and have seen its destructive fall out take the futures of several family members and friends, as well as end relationships and destroy the family unit. My relationship with my mother is virtually non existent at this time, due to her drinking and selfish behaviors. Her grandchildren hardly know her, and she seems content with those choices. I refuse to expose my kids to that lifestyle. I'm sorry you know this pain, and your concern for your siblings is touching and speaks to your character. As for advice...Duncan's post mirrors my thoughts. Obviously we would like to see the Alcoholic get help and get well, but I know how often that is not the case...So we have to seek healing behavior modification for ourselves. If they cant or wont change, we must be given the tools to know how to not let their "demons" invade our lives and try to break the cycle. There are thousands of studies that show and prove the findings that the children of alcoholics carry the legacy with them. It is proven that many children of Alcoholics grow up to be the same or marry into alcoholism or other abusive patterns. Divorce is at a higher rate among this group as well. We are unwillingly made Codependents of this by having to grow up within the dysfunction that accompanies this kind of disease. Any help or tools you can give yourself and your siblings, will help heal and prevent the cycle from repeating itself. I commend you for asking for help...and for being so honest in a public forum, you are not alone and there are so many who cant ask, so anytime we can discuss these things, we give them a voice and hopefully a choice. There are endless sites on line that you can find research info on as well.
I wish you and your family healing and hope you can be the place where second chances begin. I dont know if I've helped or told you anything that you dont already know but I thank you for listening.