They didn’t seem to treat Lee the older brother that way. From his comments it seems that he was made to feel like he was being pushed aside. Strange family dynamics. There are some families where one or both of the parents pick a favorite who can do no wrong and the other child can do no right.
That’s how they turned their daughter into the monster she is. You don’t do that. Picking a favorite to that extreme does no favors. They could have been taking her side this whole time and created her as a monster. Parents are supposed to be a representative of God, and you don’t do that when you turn one of your kids into a God by giving into their every demand. Sounds like the brother has suffered. This girl didn’t just wake up one day a monster, she was created.