Just put her in a mental hospital and wash your hands of her, she clearly doesn't wanna do the therapy that would help her, and the target of her erotomania should in no way be the person trying to help her work through it. Even if you can't prove she's been trying to murder the hypotenuse yet and she is a family friend, reputation be damned get a restraining order cause of her unwanted attention and harassment. But as someone said in a different chapter, I do not know if China even have restraining orders