Hi JustAkid and welcome! Dealing with a disordered parent is difficult enough (and you have 2!) but all of the siblings on top of it? It is a lot. Stories like your make me very glad I have only one older brother.
Not responding to her reply to your email is good. You said what you wanted to say (well done BTW) and told her how you would like to be talked to. She chose not to listen and mocked you ( :'( ). IMO, no reply is necessary at this point. You have communicated what you would like, but she gets to choose how she will act. She is now aware of where you draw your line. The next part is to decide how you want to respond when she continues to ignore your request (and expect that she will). This is where boundaries will come in---> what are you going to do or change about *your* behavior the next time she does this? Walk out? Remind her and stand firm?
But I recently went back into counseling last month and have needed to discuss the attempts I'm making at boundaries with my mother and awful anxiety I'm in. It has been causing panic attacks. I have been dealing with a lot of anger about this. I feel constant anxiety, panic or anger that I feel this way.
Though unpleasant, I think your feelings are to be expected and normal in this situation. You are changing things and challenging the status quo. You learned new things about your parents and are starting to piece things together. It makes sense to feel the way you do... .more importantly, you will feel better in time. Keep working on you and when you speak up for yourself more and more you will build confidence and be able to channel the anger, anxiety and fear. Practice! Plan out what you will do in various scenarios with your mother, g-ma, siblings. Practice saying things out loud. The anxiety and panic will lessen in time and with practice.
One of the most difficult things to deal with in these situations is the fallout that often happens with other family members and friends. As you said, not everyone is on the same page. I still have not really discussed that I think our mother had BPD with my brother and I first learned about it approximately 10 or 11 years ago. You will have to do some of the same things with your siblings as you are doing with your mother. You do not need to say anything directly to them, but you will have to allow them to choose how they will respond to you changing your role and standing up for yourself. Again, it will take time but keep at it. Smear campaigns hurt but you can not control what your mother chooses to do. I hope you siblings do not get involved and take sides, but there is no way to know for sure what they will do.
It is always difficult when one person in the family changes and the others stay in the same functions in the same old system. Your removing yourself upsets everything and you will see the others scrambling as they try to get the system back to normal. Expect it and stand firm to your boundaries. Stay out of the old system and let them figure out their own place. The only thing you can do is take care of yourself and be there for them if and when they decide to follow in your footsteps.
I just re-read my last two paragraphs and they are all gloom and doom aren't they? It is hard to talk about this stuff and not get serious because this is serious business. This is you and your life and your own emotional health that you are taking care of. You will be okay. You will get through this. Keep going for counseling and please keep posting here. We can all relate.