Hello webster9,
Welcome to the Parenting Board, we are glad to have you here!
I'm sorry to learn that your d19 is suffering with BPD and that all the efforts made have not had a lasting positive affect for her. You mention that she has had extensive DBT, do you remind her to use her DBT skills? If so, does it help?
I understand your frustration and concerns about her behaviors and mood changes. Having an adult child that we cannot at least insist they get help can leave us feeling helpless and seem like there is no way out of the situation. I think you are leading by example in seeking help from her therapist. Maybe you can talk to the therapist about using a more firm communication skill called SET (Support, Empathy, Truth) and also discuss setting limits and boundaries.
Can you take a look at these 2 links and see what you think about them:
COMMUNICATION: SET TechniqueCommunicate Boundaries & LimitsIf you have any questions or want to discuss these skills with us we are here to help.
lbj