What brothers say to tease their sisters has nothing to do with what they really think of them.
Siblings: children of the same parents, each of whom is perfectly normal until they get together.
Your siblings are the only people in the world who know what it's like to have been brought up the way you were.
Brothers and sisters are as close as hands and feet.
A sibling may be the keeper of one's identity, the only person with the keys to one's unfettered, more fundamental self.