April counted the four turtles as brothers, even though they never called each other that.
If they had to rescue each other it was always "let my friend go" never "my brother".
They were raised together, and they even acted like brothers. But they talked about each other as if they were only teammates. They didn't even refer to the person that raised them as father. Their relationship was always toeing the line between a family and a clan.
But they were the closest family she had ever seen, so she guessed it didn't matter what they called each other.