I don't think I would jump to alcoholism here...

I'd confront her about your feelings, but I would approach it as more of a "I'm finding myself preoccupied by my concern about you, and here are the things that are concerning me..." rather than "I think you're an alcoholic..." although, maybe you should confront that too. Hm. IDK.

Have you had issues in the past with people with substance abuse problems? I'm just thinking maybe some projection....