What a tough, sad situation.

However, I have to agree with everyone else. There are "homes" or "programs" for young people such as your cousin. They will learn what they need to know to take care of themselves and to live on their own. They will also be helped to find jobs to help support themselves. I'm sure they will also help to get her to finish high school....if she's even going to high school?

I know of one such young lady. Her parents are the complete opposite of your Aunt and Uncle. They are wealthy, probably mid 60's and in excellent health. Their daughter lives in her own apartment, has a job and has a social network of people to help her out in the ways she needs help. She is the sweetest girl, just adores 60's music and I Love Lucy, and functions quite well considering her "disability."

I say the sooner there is intervention for your cousin, the better off she will be in the long run. I know it will be tough for you to "turn her in" or "turn the family in," but really, you're doing her and them a favor, not a disfavor as they may originally see it.