And like denny said, you can't force someone to hit rock bottom, but you sure can speed up the process of them getting there. Don't protect them from themselves anymore. Don't try to keep them out of trouble. Don't lie for them anymore. Don't give them money. Don't try to stop them from drinking. If they want to do it, they'll find a way.
Keep posting, keep reading, it will help you to deal. Hugs.