Ethan MacArthur's last years

In hell arrives a boy, Ethan MacArthur, he initially explains how he's affected by a mental disease, developed from birth, which makes him behave like a child, unwillingly and randomly.
He starts telling his story from a day, when after school, where's he's known for his bully behaviour, and his violence, and where this disorder of his isn't known of, his brother finds a way to make him pay for his behaviours.
Here starts the reading of his memories of this last few years of his life...