Mariah Carey's ailing sister Alison, has made a desperate public plea for help from her superstar sibling. The shocking video appears on DailyMail.com and it comes after she says she was the victim of a home invasion. "Mariah, I love you, and I desperately need your help. Please don't abandon me like this," she said. Alison says she is facing serious health issues including being HIV positive. She's also admittedly had a troubled life of drug addiction and a record of prostitution.