You can tell her what you think, but I doubt she'll listen. She need a scare before she realises what she is doing. We have the same problem with a family member, again her parents were alcholics and she had phoned many a time at 2.00 in the afternoon drunk asking me to take one of the kids to A&E because they have hurt themselves and she can't drive. Been going on for years. Finally had enough, got sumoned round after a text saying she needed help, to find her and her husband having a huge fight and their 12 year old daughter having a panic attack. Sent them both out the room, calmed down the daughter, tod them both some home truths and took the daughter to stay at mine for the night. Up shoot being, she says she will get help and stop drinking, needed someone to be honest with her. I have my doubts as its a hard cycle to break, but she knows I'm there for her, but will not pamper to her any more.
Your friend is lucky to have a some one that cares for her, but at the end of the day only she can help herself and that means she needs to realise what she is doing and want to stop, I know its not easy to sit back and watch it happen.
Good luck to you.