She's drowning

And I can't help her.
I'm talking about Adam's cousin. She's dating a guy who has been in rehab for a really long time. He's been in detox since Deer Opener. That's like 3 weeks. I guess he's cheated on her a few times while in detox/rehab (the facility is in the cities, about 2 or 3 hours away). She's chosen him over the family pretty much every time. She didn't come to deer opener so that we could have a birthday party for her daughter. She didn't come to the Thanksgiving we had at the IL's house. She didn't meet up with Adam and I when we went out to eat on Friday. She's forming her life around this scum bag that no one in the family likes. I asked her if she's going to bring him to the house for Christmas. She said "Maybe. Depends on if he's out of treatment. And if he is and he comes, there can't be booze in the house at all." Umm that don't work in the Goose's house. There is always wine, wine coolers, and harder alcohol. The thing I don't understand, is her dad is a recovered alcoholic. He will have a non alcoholic beer with the rest of us if he feels like it, but most of the time he's happy with a Pepsi or some juice. Her dad even thinks he's the scum of the land. They didn't meet up with us for lunch because it was at a brewery/sports bar type eatery. All because there was booze in the place. HELLO! Does that mean you don't go into a grocery store because they sell it? Do you stay out of someone's house because they could have alcohol somewhere? Seriously, its called self control. They really do teach that shit in rehab. Pisses me off because he's seeming to be the kind of person who only goes into rehab to avoid jail time. Adam and I are willing to bet that is the deal.
I used to be SO close to this woman. We were closer than best friends. Her daughter used to come running to me when I came in her house. Now it takes a long friggin time before she even lets me ask for a hug without running away. This woman was there for me in so many ways while planning the wedding and all. It seems like she just doesn't care anymore. She used to always tell me that having a boyfriend wasn't in the cards until she got everything settled with her daughter's father. Guess its all taken care of because she never used to ditch family for a guy!
I really wish there was something I could do to show her that he's bad news, But I'm not stupid. I know that you can always lead a horse to water but not make them drink. You can also send a boy to college but you can't make him think. She's going to have to find out the hard way and my heart breaks for how its going to effect her. Where are the life jackets for times like these?