If my niece only has a medical paper signed by a doctor, does she have the right to not tell us where my brother is?

Brother has right to visit relatives. An ADA Civil Rights Complaint may be in order . Brother has right to family visitation. Isolation and alienation that serves no purpose for your brother is an abuse.

Would be nice to see what the paper says. It may be that the doctor feels pasrticular people are not good for the brothers health.

97yearoldmom, I suspect there's a lot of family friction going on and the OP didn't want to address it. This question was posted 6 days ago and she hasn't responded.

Your niece might not have a document saying she can legally keep your brother away from you but I'm thinking that neither is she compelled to tell you where he is. Sort of a "hers to know and yours to find out" situation. Is there another family member who could advise you? Where was he last? Perhaps there are clues there. Why would your niece feel she has to hide him? Perhaps you could check with your sheriffs department to request an inquiry to make sure he is safe or you could seek legal counsel.

What "medical paper" are you referring to? A HIPAA authorization? If so, this is independent and unrelated to the location of your brother.

Your profile states you're caring for your mother but doesn't mention your brother. What's his situation? Is someone caring for him? What are his medical conditions? What's the history of your relationship with him?

More information is needed to understand the situation.