If your concerned, you're concerned so own it. I think most people might think that's a bit much for someone to drink. If you're asking if she is an alcoholic, I wouldn't know. I never finished my last glass either, by then I was too wasted. I didn't show signs of intoxication, so I've been told, but I was in a total blackout. I'm an alcoholic.
When I am in active addiction, I don't know any way you could bring that subject up without me being angry. Hopefully someone will come along soon with some better proposal.