Yup, I had to cut off from my mother and sister for similar reasons. The active alcoholic and even the alcholic in early recovery can be incredibly delusional. They cannot tell the true from the false, they don't know how to relate. This comes across as negative and damaging behaviour towards friends and family and in my particular case, I found it impossible to establish healthy uncle/aunty,niece/nephew grandmother grandchildren relationships. They were just too toxic and I have had nothing to do with them for many years.
On their mother's side the kids have great family ties, and with all my extended family, that part is just brilliant. But the evil duo, my mother and sister sit on the side hating me and all the family (there are over 100 of us) and basically cut themselves out of any form of meaning in their lives.
I don't know if that is the right thing for you to do, but I have never lost a moments sleep over it.