Dealing with schizophrenics?

My boyfriend's mother has schizophrenia. I've lived with her the past 5 years and it's getting out of control. I don't know what to do. She's been 302 before but it made things worse. She's accused me of trying to poison her, trying to kill her so I can take her house, being a prostitute, cutting her hair in her sleep, etc. She's hid my stuff, cut my clothes. messed with my toothbrushes, threw my stuff in the trash, and berated me. It's not just me, her and my boyfriend fight all the time, because it's really hard to deal with. She's thrown eggs at him and broke his stuff. The only reason he sticks around is because she wouldn't be able to pay the bills without him. I try to feel sympathy for her, but she is not a nice person. I've known schizophrenics who were nice people, but she is nasty. Sometimes I don't leave his room for the entire day because she is downstairs screaming to herself. She's extremely bitter and is always screaming to herself about the lawyers she used to work, and her sister, and the IRS, and the bank are out to get her. I don't know what to do. Yesterday's episode was so bad. She was drunk, and screaming at the top of her lungs from 10am- 9pm, trying to start stuff with everyone.I didn't leave the room all day. When she's "normal" I try to talk to her about getting help, but it only triggers her. In the midst of all this, I feel like I'm losing my sense of reality and normality. I can't continue to live like this, but it seems like there's no answers.