Trivia: Some of the campers seen getting off the buses at the beginning of the film are relatives of the cast and crew.
Trivia: The director dedicated the movie to his mother.
Trivia: The original artwork for the Sleepaway Camp Survival Kit box set was recalled after complaints were made by the Red Cross.
Answer: Watch his first scene at his aunt's. He doesn't speak at all. Clearly Angela/Peter has had a withdrawn personality since the death of his father and older sister. So doing activities with other kids is one thing he wouldn't do, as for eating, a lot of kids don't at first if they miss home.
Rob245