Foil
Character Role Analysis
David and His Father
David's father changes his life by giving him cancer. David changes his father's life by being a walking, flesh-and-blood embodiment of that terrible mistake. When David's father, no longer able to live with the deceit, finally admits to what he's done, David realizes his family really is that messed up—and shortly thereafter, he leaves home.
At the end of the book, his dad's still trying unsuccessfully to get his mom to smile for Christmas pictures, still maintaining the façade that they're a happy family. David, on the other hand, realizes they aren't, and gets as far away from his mom as he can. He's not going to be like his dad and spend the rest of his life attempting to please her.