In Freak the Mighty, we learn that Killer Kane (Max's father) is out on parole and has returned for his son on Christmas Eve. He kidnaps Max and initially seeks shelter at Iggy and Loretta Lee's apartment.
Iggy is the leader of the Panheads, a motorcycle gang that strikes fear into the hearts of everyone. Max is surprised when he meets Iggy in person, for the formidable man cooks up hamburgers for him and his father.
Eventually, Iggy takes Kenny and Max to a tenement apartment belonging to an old lady. He tells Kenny that the old lady is away visiting her sister for the holidays. Here, Kenny intends to hide until Iggy can procure him a means of escape from town.
During this time, Kenny tries to convince Max that he didn't kill Max's mother. He tells Max that he's been unfairly judged (on account of his size) and insists that he's been deprived of freedom because of this unfair characterization. Kenny also laments that Grim and Gram (Max's grandparents) never accepted him as a worthy husband for their daughter.
He maintains that he sent presents and letters to Max over the years and, having heard that Max never received them, insists that the boy's grandparents were trying to turn him against his father. Basically, Kenny tries to "reprogram" Max while holding the latter hostage. Far from regretting his actions, Kenny doubles down and insists that the "real" crime was the one committed against him.
He maintains that his imprisonment was an injustice. To right this wrong, he intends to take Max far away and begin a new life with him.