Hi electricleo

Since when has your sister been exhibiting what you now consider BPD traits? What would you say are her most difficult or troublesome behaviors?
It is unfortunate that she refuses to seek help. Do you feel like she at any time perhaps has acknowledged that there might be something wrong with her behavior?
I understand your concerns for your mother. Living with a BPD family-member can really take its toll on people. Does your mother also believe your sister has BPD?
We have some material here that you could perhaps print out for you mother. Certain communication techniques can be very helpful when dealing with people with BPD:
Express yourself: S.E.T. --> Support, Empathy, TruthAssert yourself: D.E.A.R.M.A.N. --> Describe, Express, Assert, Reinforce, Stay Mindful, Appear Confident, NegotiateYou say your sister doesn't talk to you, when did this start and did anything in particular lead up to it?
If I find a personal support group in that area, I will let you know. I did find some other links for support in that area that you might find helpful:
https://therapists.psychologytoday.com/rms/prof_results.php?city=Hamilton&state=ON&spec=196https://groups.psychologytoday.com/rms/prof_results.php?sid=1447924738.439_16329&city=Hamilton&state=ON&spec=196Take care