B52s post is good advice, however if no one opens a 'can of worms' the problem continues, You may have to be the bad guy. The ad by Carrol O'conner, about doing every thing you can do is right on. Make waves, open cans of worms, Have a heart to heart with sis, and your parents, All together if possible, and don't worry about embarassing her. Believe me she is not just drinking after the kids are in bed. Its time to see the elephant in the living room.