Controlling/abusive parents?

This is a bit of a tough one =/. My girlfriends parents are controlling and abusive to her. No they dont hit her, they do however rip her apart emotionally. She suffers from bipolar II disorder (I too have the disorder but i am being treated for it), and does not receive medication or any type of therapy. Not even her parents help her or take her condition seriously. They scorn her when shes depressed and yell at her when shes crying. They see her occasional hypomanic episodes as acting out, and that she should be punished for it. They bait and tease her into arguments and when she finally snaps on them, she gets grounded.They are fond of using this tactic when they know she has plans, especially plans with me, almost as if watching her disappointment is enjoyable to them. Both parents are heavy drinkers (from what Ive seen, they drink nightly to the point of being smashed, not just buzzed). the mother is the type of drunk that when inebriated, she will let out her inner feelings and take her anger out on others, mainly my girlfriend. I have experienced this first hand when i went over her house for dinner. At first i was treated with generosity...but the night slowly became more and more awkward (even a little scary) when her parents got hammered. Her dad kept making jokes about the gun he has (yes they were jokes, but i got the feeling they were warnings).Her mom was suddenly slurring out sentences hinting that she did not want us together. A little bit about myself. Im a straight A student attending college 2 years ahead of time. Im a prospective doctor and i am extremely well mannered and respectful. I am in no way a bad kid....back to the story.Whenever she is able to come over my house (which is rare) it is almost like a vacation for her. My family treats her with extreme warmth and makes her feel like a member of the family. My mom even offered her number to my girlfriend if she ever just needed someone to talk to. It is very hard for me. I care about her so much and I know im probably the only thing keeping her together. I want to get her help for her bipolar disorder because i know the pain it causes on its own, I cant even imagine what its like when you have parents like hers. They are both anti-medicine and they'd probably scoff at the idea of her going BACK to therapy. Note that its not just me, her parents dont even let her see her friends. It is far beyond the clic scenario of overprotective parents. they dont let her out, not out of love or worry, but for the satisfaction they get out of watching her get upset. I just want her to be happy. Me and my mom are both very worried about her well being, but obviously we dont have the right to do anything about it. Even if they just got her the help she needs, id feel better, even if i still couldnt see her. Id like nothing more then to tell her parents how ashamed of themselves they should be for hurting such a beautiful intelligent girl...but I know that would only make matters worse.Any advice would be generously appreciated =/