High-functioning alcoholism is a thing. It doesn't matter, though. Like the others said, unless she comes to terms that it's a problem, she will probably always consider herself just a "heavy drinker". I used that term to describe myself for far too long before I came to terms with what I am. However, if someone had told me I was an alcoholic (and they did) I would have been very angry with them, and possibly distanced myself from them.