My siblings and I were born over a 16 year period. The initial part of my parent's marriage was an Ozzie and Harriet experience. The middle and latter years were chaotic with arguments, heavy drinking, financial difficulties, and a lack of stability in private. In public, life was always "Ozzie and Harriet" and all secrets were to be family secrets. Now, my father is dead and my mother functions in an unhealthy way that the older siblings and younger siblings refuse to acknowledge. Being the middle child, I had a view of the good and bad times. Since I am living closest to my mother, I have to deal with day to day issues. The "myth-keepers" make caregiving difficult because they refuse to deal with reality. Also, I have to tiptoe around them when I talk to them to avoid confrontations. I am ready to "divorce" everyone as much as possible with the exception of my mother. Am I the only person going through this type of situation?
I can understand your desire to "divorce" your sibs. Maybe that is best at this time. I probably wouldn't spend a lot of effort trying to avoid confrontations, but I'm the oldest, the bossy one, not the middle child peacemaker!
You are definitely not alone. I don't think you can deal with this in a way that will satisfy everyone, so satisfy yourself and your mother.
You are a very insightful person. Your mother is lucky to have you.