Hi anon123;
Ouch -- I hear the hurt in your story. When pwPDs (people with personality disorders, whether full-blown/diagnosed or "just" traits and behaviors) do relationships, control is often involved. It seems like when you're part of a family system where BPD is at play, you can't just have normal independent relationships. I'm so sorry you're going through this.
There's sometimes a rigidity around how pwBPD do family roles and relational roles, and I wonder if it's because pwBPD struggle to have a sense of self truly coming from the inside. So, to stabilize chaotic emotions and an unstable sense of self, if they can make everyone around them "play their part", perhaps that gives stability.
It can be helpful to learn more about
the Karpman Drama Triangle as one model for how relationship interactions happen when a family member has BPD. Take a look at that thread and let us know your thoughts -- I'm wondering if sometimes you want to rescue your dad from your brother?
Is your brother younger or older?
And one more question came to mind here:
He threatened to create conflict between me and my in-laws / husband.
How is your relationship with your H and his family? I wonder if you could give them a heads up ahead of time -- wouldn't have to be lengthy -- that your brother is having some challenges and may try to tell them things about you, and if they ever have any questions, the door is always open with you and you'll answer them.
Sometimes we fear that the pwBPD in our lives are so persuasive and powerful that others will believe them right off the bat. This isn't always the case.
anon123, fill us in on how things have been for you these last few days, whenever works for you. And again, welcome;
kells76