It sounds like they're bonkers. I'm sorry you have to put up with that stuff. I assume there was lots of abuse within the family?
There was for the ex and the sister. The sister is older and the ex looks to her as a savior almost. She completely excused - and still does - her behavior when the miscarriage incident happened (the sister wasn't told about it first and went on a rampage screaming at the ex and told the ex that she was nothing to her).
Their dad left when the ex was 2 or so. The mom is crazy. Period. Moved like 60 times in five years and was blind to what was happening. Told the two sisters they were lying and all that. Good stuff (said sarcastically). It took their grandparents to rescue them.
I want to say the abuse was limited to them two...I've heard nothing of if the mom was or not.
There are moments in this life when you are so confident in the rightness of your actions, that not even for a second do you consider the option that you might be wrong.