Hello sisterBPDtn and welcome here !
I can relate to your anger. My FOO (family of origin) was dysfunctional too, with a BPD mum and an enabling dad. I never really realized the dysfunction until after I got out of a very messy relationship with a man with BPD. It was like a lightbulb going off in my head. I started reading about BPD, and everything fitted. It was like I was reading about my own life.
I wanted to understand about BPD, so I would never make the same mistake of entering a dysfunctional relationship again. And the more I read, the more I became angry. Meditation helped, but I kept reading and the meditation helped less and less :-)
I think what helped to slow down the anger for me, was realizing my mum would never change. Here we call it 'radical acceptance'. Maybe you can take a look on the link here :
https://bpdfamily.com/message_board/index.php?topic=89910.0What also helped was digging into my family history and trying to understand why my mum became the BPD mum she was. I did not get all of the answers, but I tried to picture my mum as the lonely little girl she must have been. And my dad as the angry little boy who was left alone by his narcissistic dad and his own BPD mother. Of course I didn't suddenly agree with the behavior of my parents and their methods of raising their children. But I started to understand, and slowly my anger started subsiding.
I also learned how to not be codependent myself - not with my mum, but also with other people. I read about boundaries, and how it's ok and even necessary to have them. I also learned that other people's problems belong with those people, and not with me. I cannot fix the world. I have always wanted to help others, even when my help was not asked for. (I guess some people find that even annoying, but the least I can say about it now is that it's being codependent)
I think becoming less codependent also made my anger go away more and more, because the unwanted results of my dysfunctional upbringing started to diminish a little. I got more in control of my life, what I wanted and moreover, who I wanted to be.
When I read your story it strikes me that you want to do the good thing and help your sister. But is your help asked for ? Or even wanted ?
Also you desperately want to 'drag' your mum into the story. Why ? You cannot live your mum's life, you are only responsible for yourself. If your mum decides to not visit/care for your sister, that is really your mum's choice. In my opinion you cannot only not force her, but it's also crossing a certain line, of someone's independence. Please also keep in mind that your mum is BPD, which generally means low empathy. I for myself have hoped practically my whole adult life (I'm 38 now) that my mum would care for me, and show love. Now I realize she won't. Never. Because she *can't*. You cannot squeeze a stone.
So what I'm trying to say is that you might want to give it a try to step back a little from other people's lives - even when those other people are family. They might have some dysfunction, but they are still fully responsible for their own live. You are not, and you should not try to be - in my humble opinion at least.
Please keep posting, we are here for you.
Fie
xx