Upon her discovery, Rusty did have an unhealthy obsession with her. Since she had several degrees of separation from Hollywood due to her job, he wanted to connect with her to use her as his ticket to the biz. Given how she was probably completely blindsided or re-reminded by the aspect of having a twin brother that was given up at birth, it was perfectly fine that she either needed time to process or wanted nothing to do with that. (Given how this is also speculation on my part as well as Rusty's side of the story, it should all be taken with a grain of salt) Rusty refused to accept that she had a say in how she chose to handle this. Even going as far as attempting to use the courts just like he did with Erika.
My theory is that his obsession with these types of women is because he needs a stand in for his bio sister so that he could "feel her love". But once again, this is all just retarded speculation while we wait for Rusty to do his thing.