Doing the "lets see what our readings are" thing is about the only thing you can do.  I'm sure she would know she's got a problem drinking too much but as much as you'd like to help, to be honest, it's her business how she lives her life.

I'd be worried about her hurting someone, driving while still affected in the mornings but unless she's caught in a RBT or has an accident, I don't think anything you say will change her.

It's hard to watch someone slowly kill thmeselves but her choice.