What would the book look like if the author showed the responces to Jamie's letters?

In the book Punkzilla, the main character, Jamie, is writing letters to his brother, Peter, who has cancer. His brother has asked him to leave nothing out, so Jamie tells him all the details of him running away from military school, stealing ipods, and getting robbed. But what I think what would make the book better would be if they showed Peter's leters back to Jamie, so we could see his reaction. I think, they could both build on what the other said, rather than having only Jamie write, so it just shows his side of it all.