My half-sister is from my dad's first marriage, and 18 years older than me. She married her (now STBX) husband at twenty, so I really do not remember a time where she lived with us, nor a time without ex-BIL in my life. We weren't close when I was young — mostly she popped in for Christmas/dad's birthday twice a year and that was that. But as adults, we became closer. I am closer to ex-BIL though, as I find sister to be hard work at times, whereas ex-BIL is very easy-going and has a lot of the same hobbies as me and my DH. Things like winter mountaineering, white water rafting, etc. Sister is always invited to such excursions, but doesn't like outdoor activities. They both regularly have dinner with my family and take my DCs out to cinema trips and so on.
They are now separating. Sister alleges financial abuse at the hands of ex-BIL, ex-BIL alleges financial abuse at the hands of Sister. Ex-BIL is just thrilled to remain in contact with me and my family, Sister is constantly running down ex-BIL to my kids. Things I think are inappropriate to tell DCs about their uncle, such as telling 13 year old DD about dead bedrooms!
Sister has now just found out we are still in contact with ex-BIL and his hit the roof. I think she's out of her gourd to expect me and my family to cut someone out I've known since literal birth on just her word. She thinks I'm being a terrible sister and bad feminist.
Not to be horrible, but she is prone to exaggerating and ex-BIL is not. I am more inclined to believe his account than hers.
AIBU ? Would you side with your blood relative ?