What I said in my post earlier. Also, if this psychologist is not useful, try other ones. If she believes she has BPD, a form of therapy that is often recommended for that is DBT - many people find it helpful, your ex could find a provider and get into that directly. I don't think one needs a formal BPD diagnosis to participate. It is also possible that psychotherapy is just not for her in general, but it may be worth experimenting with different providers a bit.