I've simply distanced myself by not being available. In time, they were happy to see me now and then and stopped the drama (at least in front of me). That said, my mother lives with me and distancing myself from siblings while she is sharing a home has been a challenge, yet not impossible.
I did not have to totally cut off family in order to get some relief. Good, solid boundaries can help.
I am sorry you are going through this.

WC