spoilerz
he didn't rape Isaac (from what i read in the novel. Novel was kinda messy becoz of the translation but i think it's near to the correct trans) Isaac suffered sexual abuse (no penetration) physical abuse and the step dad manipulated him throughout the years in living with him. that's why he ran away without going back to Cole. If i remember correctly, he also manipulated Isaac's biological father and was the cause of his death.

Yo I'm actually scared for the next chapters. I saw one post saying the hardest part of the story is just about to begin wtf does that meaan