So like why WAS Horrid Henry's family always antagonistic to him? Clearly his parents raided him like that and then they punish him for acting out. It's fucked up.
The glass child effect, coined and popularized by Alicia Maples, is a phenomenon by which a child with a disability or chronic illness makes the other’s needs secondary if not tertiary to the needs of the emotionally spent parents and sibling child. Peter’s spoiled self-centeredness contrasted by Henry’s attention seeking behavioral patterns make it clear both are neurodivergent, but “Horrid Henry” is the only one demonized for traits both exhibit, because that is the only time his parents truly notice him.