My daughter-in-law has a half sister that is not wanted in either Father or Mother's homes. What can she do to get her to be able to live with her and her husband?

I don't think 'rights' have anything to do with the situation. There is no law that can force the family to accept her. It is entirely up to the family and the dynamics of that family. You don't say the reason why she isn't accepted. Is it because she is a half sister and not thought of as one of the immediately family? It is too bad they feel that way. Maybe the family should sit down as a whole and discuss the issue, the issue may not be applicable to this woman any longer.

Tick

What is the age of the person in question? Guardianship is a possibiity. Rights? There really aren't any.