Now my question to you all is what can I ask him to determine if he can and will help her overcome the BPD coping mechanisms she has and begin to react to life, me, others more reasonably?
You said that he established that she had BPD 6 years ago.
If he is vaguely competent at his job, then he is already doing this the best that he can.
YOU react to her BPD coping mechanisms. They are awful, so this is understandable.
Spend your energy working on finding more constructive ways for YOU to react to her poor coping mechanisms. The "natural" reactions you have make things worse. Change what you can easily change: your own behavior.
Read
the lessons here and work on the ways you can help the situation by changing your own behavior.