You brought up the drinking sisabel because it's not healthy. Your daughter knows this but has decided to turn a blind eye, even be an enabler.

I hope you are right in that while there is a problem they are so far being careful. You can't change your daughter's choices, but you can set boundaries. It's not always easy as you are finding out, yet, it's important you have boundaries otherwise you will face being used and walked all over, this much you know through experience.