First I want to say Hi to everyone as this is my first post and want to Thank you all for the support you provide everyone!
So here are the details on my situation...
For the last 10 years I have been dealing with my sister's ongoing mental health issues. It has put a giant strain on our family. Currently my sister lives with my mother who is 76 years old with cancer and a bunch of other medical issues. I am pretty sure the stress my sister has brought on her has deteriorated her health. Just yesterday my mom called me that she was also fed up with my sister.
I am not a medical professional but once I started to see signs of mental illness I started to research and read books on BPD which has lead me to believe that it is one of her conditions. Not sure if there are more because she shows signs of other things as well.
The behaviors she shows are:
1) I cannot have a simple conversation without her crying every single time.
2) She has delusions and lies in every conversation. Making herself feel more important and more successful.
3) She has not had a romantic relationship in over 10 years and stalks athletes and other people through social media who have no interest in her.
4) She isolates herself and has no friends. She only deals with our family members who visit my mother.
5) Paranoia. She always says someone is following her or tracking her and keeps all the blinds closed at her house and her cellphone turned off at all times. But then will use my moms cellphone to text all our family.
6) She has not been able to hold a job for over 10 years. Any job she tries only last the maximum of 3 months if that. She always says she is in school for 15 years to be a doctor, cop, nurse etc depends on the day of the week

7) She has not been diagnosed because she says she is a prophet from God and she does not need help. I have offered to go with her to therapy but she will not even consider it at all.
Throughout this whole time I have tried my best to keep her comfortable and at peace but I am so over it. Everything revolves around her feelings for that day. Every time the family is together it always leads to a discussion about her. Literally she has been the center of conversation for about a decade.
I am happily married for over 12 years. My marriage is the one thing that keeps a balance for me. My wife has been 100% supportive of this whole ride. I guess since I am the most successful and level headed person in our family everyone automatically decides I am the one that needs to deal with this. However, no one ever thinks about the issues that I might have. I have always dealt with depression since a child because I do believe my father was also an undiagnosed BPD. My sister and him are pretty much identical and put my mother through hell. I have been able to deal with my depression by staying positive and meditating etc. However, dealing with my sister affects my depression greatly.
I know everything I read says to have compassion for these people, to try and understand them and not take anything personal. But how much is enough when you are sacrificing your happiness for someone who will not change at all. My Mother always says speak to her, call her but I end up worst after the conversation once she starts going into a bunch of lies and delusions. But to my Mother I guess that is ok because in her mind my sister is a lot worst off than me. I do feel guilty at times because I try to go no contact with her as much as I can but I have to consider my health as well.
I would appreciate any advice you guys can give me on this. Thank you soo Much!