How do I get a mentally ill woman to stop coming by my house?

my bf was smoking in your courtyard and the mother of our upstairs neighbor was out there. she is homeless but visits her daughter frequently. my bf briefly chatted with her and now she comes to our door several times a day. last night she came to the door and told my bf he has and eating disorder and that i reminder her of kurt cobain (eventhough i've never met her). i'm guessing she is an unmedicated schizophrenic. i don't want to be rude to her but i would like for her to leave us alone before things get out hand. any suggestions?