I definitely remember some of the plot details wrong, but I believe that one of the teachers hated Reese, a very dumb loser, and was purposely trying to fail him. So his brother Malcolm, a very gifted student, cheated on behalf of Reese to save him. They get caught, and the teacher presented Malcolm's mom with the choice of which child's future to save: either reporting Malcolm for cheating and possibly ruining the only one in the family with a bright future, or just failing Reese and letting a loser with no future get a head start on failing at life. She unhesitatingly said that she would sacrifice Malcolm to save Reese because Malcolm would land on his feet and be ok no matter the circumstance.