Finding Audrey question

So I have been trying to find this book. I don't remember the title or even the author. It is a fiction book, not necessarily a children's book. It starts off with this kid and his friends. They are going to get into a fight with some other kids. The other kids pull out a pipe getting ready to start a fight and beat them up. The main character ditches his friends before the fight. The book is told from his point of view the entire book. He finds a kid in the woods, which is described as a kid living among a bunch of sticks. He's kind of a weird child, making explosive noises with the sticks and living in the woods. They both have a big imagination and become friends. Most of the book is the main character and this kid he found in the woods. At the end of the book, they find a man who is a construction worker. They wanted to mess with the guy at a construction worker's house. That's all that is remembered about the book. The main character's name was something like Billy or Willy, something with an -illy ending. The cover of the book might have been red. Those are all of the details I have. Thank you!