Hi Ceres and welcome to the family!
I'm glad you've found us here. We're a supportive group with a lot of experience and tools we can share. Relationships with pwBPD (people with Borderline Personality Disorder) can be difficult in so many ways. But so many here (including me) have found ways to make things easier.
Encouraging a pwBPD -- or any disorder or problem, really -- is a tricky proposition. So many members here report family members refusing treatment so it's a common problem. We have an article about it you might want to check out:
https://bpdfamily.com/content/how-to-get-borderline-into-therapyFear of abandonment is also a BIG thing with pwBPD. It may seem counter-intuitive, but that frequently leads to a push-pull dynamic, or to the pwBPD pushing their loved ones away in a sort of "I'm going to leave you first so you don't leave me." It can also lead to extreme clinginess.
What's the state of your relationship right now? What are the "antics" you've been ignoring?