Welcome Porch Swing: I'm so sorry about your abusive past and your current situation with your sister, and the death of your father. I have great empathy for what you are going through with your sister in regard to your father's estate.
My sister developed very strong BPD traits when both our parent's health began to fail and they both passed within 6 months of each other. My sister and I were "co" on everything: financial and medical power of attorneys and co-trustees on our parent's trust. I have a taste regarding how difficult it can get.
SETTING BOUNDARIES should be helpful. Boundaries are for you and your benefit. You will be the one to enforce them consistently.
One boundary to use when she gets abusive during phone calls is to say something like this in a calm voice: "It's important to me that we have a mutually respectful conversation. That doesn't appear to be possible right now. I need to let you go and we can talk at another time. (then just hang up the phone, don't let her keep talking, just go)
AVOIDING CIRCULAR ARGUMENTS is another skill you will find helpful. It instructs you to don't JADE (Justify, Argue, Defend or Explain).
You can't change your sister. The only thing you can do is use boundaries and various communication skills that can make things better for you.
If you want to share some examples of your sister's behaviors with us, we can help guide you to some more lessons. Some people like to read lessons and then come back to their thread to check their understanding and practice some skills.
We look forward to hearing more of your story and supporting you through this difficult time.
PS: Click on the green words above to get to the lesson links.