The Sledding Hill by Chris Crutcher

Eddie Proffit has lost his father and his best friend in two horrific accidents within a short time frame. Eddie is considered a problem kid because of his hyperactivity and tendency to speak before thinking. When Eddie sees his dead best friend Billy, he freaks out and becomes mute. Eddie finds comfort in a book he is required to read for class and then becomes involved in a censorship battle at his school when the local minister challenges the book. Narrated from the perspective of Eddie's deceased best friend Billy, Crutcher takes aim at censorship going so far as to write himself into the story. The book becomes rather political with a lot of speech-making, which I think takes away from the book and the books overall message, which is important.