And I hope you'll take this constructively when I say your advice/solution is a little naive. I DON'T see or speak or communicate in any way with the family member. That in no way however, prevents her from continuing pursuit -- stalking -- which I do not want or, given her "title" and other issues such as knowing my SSN, etc., inserting herself into and interfering with my life, making or chaning decisions on my behalf to the "correct" ones, etc. One example, as a robbery victim a few years back, she not only somehow came to know about it, but contacted the state attorney's office and got my contact information which I had only established a week beforehand (which was/is probably a breach of ethics and attorney-client privilege). If she can do that sort of thing there, based on the claim 'oh, I'm his mother, and blah blah blah,' it can be done with medical, or financial, etc.
So you see, you're wrong. She can claim her relation to me and relevence in my life to all sorts of third parties who are conned into believing her. It's hardly a matter of just avoidance or ignore it and it'll go away.