He was in a tracked high school of some sort, and he was in track D, meaning he was taking classes two and sometimes even three years behind other students. If I’m right, the first two years of high school for someone in this track is extremely slowed down/watered down versions of normal classes.
Pat would have been far, far, far better off in votech followed by earliest possible admission to the Army. He would still be a dumb, fat, broken-brained pigman but would have some discipline, wouldn’t have abandoned his kid, and would have some type of skill.