Hi, and welcome!
Well, the fact that she mentioned rehab is a good sign. She may wrestle with this a while longer--it isn't unusual for someone who knows s/he has a serious problem to get cold feet when it comes to actually QUITTING drinking.
AA is a great place to get sober and stay that way. My first husband got sober when he was 21, and he just celebrated 35 years of sobriety.
It wasn't quite clear to me--do you think her boyfriend is alcoholic, too? It can be tough getting sober when you're living with an active drinker, so rehab might be good if only for that reason. The bottom line, though, is that the desire to recover, and how she goes about it, are up to her.
I second the suggestion of Al-Anon--it was a real lifeline for me when my second alcoholic husband went back to drinking (after almost dying of it).