Hi Nina88,
It is clear that you care about your family-member very much and are concerned about her welfare and how her behavior impacts your family. Your family has also been dealing with some other significant issues lately which only makes this situation more difficult.
At what point did you begin to suspect there might be something more going on with your sister than 'just' regular problems all people deal with? How long has she been exhibiting what you now believe are BPD traits?
BPD is quite a challenging disorder, yet there are things we can do to improve our interactions with our BPD family-members. To help you communicate with your sibling, I encourage you to take a look at some communications techniques described on this site:
ValidationExpress your truth - S.E.T.: Support, Empathy, TruthPeople with BPD are often quite sensitive/volatile as a result of their distorted thinking and perception.
These communication techniques can help us minimize the likelihood of further conflict, while maximizing the likelihood of getting through to the other person. They also help us stay more calm ourselves.
I am glad your father survived, though sorry he required such a serious operation. How is he doing now?
Take care and welcome to bpdfamily
The Board Parrot