Hi Tightrope walker,
Basically I am validating her feelings and taking her phone calls for a limited amount of time. I encourage her to get counselling, go to an Al Anon meeting. etc. I no longer send extra money (she has been on the verge of bankruptcy several times paying her sons bills, fines, etc.).
sounds like a reasonable strategy dealing with your sister. Validate her (helps her to be a bit more sensible and avoids invalidation). Having boundaries with respect to the time and money you invest into her is a sensible line to draw.
There is not much else you can do. You have better use for your resources for the healthier and less independent family members.
There is no telling if the calls will end in her angry at me or blaming me for something I had nothing to do with.
It may be worth having a standard way of dealing with her when she becomes abusive. Tolerating abuse only breeds more of the same. Respect is critical to a relationship with a pwBPD.