It's the Big Friendly Giant. It's about how within a group of man-eating giants, there was one who didn't believe that eating people was right, so he suffered without eating them and ate putrid Snozzcumbers instead. He catches dreams with a butterfly net and blows them into little kids' rooms at night. He distroys all the nightmares he catches.
I think your son should give these books a try. They're great. They're almost novel size, around 200 pages each, but they're really written to grab your attention.
Like I said, I barely read anything growing up but I read nearly all his books. If he wants to go to Charlie and the Chocolate factory, you can make him read the book first before he is allowed to go.