What were the changes Henry noticed in Wilson? On what pages of what version?

Wilson started off as a show off with a short fuse. He talked a big talk about his valour and courage in battle. Like Henry, it turns out that Wilson ran too in the face of battle. Wilson changes after this. He becomes more contemplative and introspective. He matures about the horrors of war and his abilities and disabilities. In Wilson’s letters, Henry sees weakness rather than an expression of humanity. When he realizes that he still has the letters to Wilson’s family handed to him before the battle, Henry does not think to spare his friend humiliation and give them back. Instead, he considers them a token of protection against his own shame.

Quote for Henry's transformation.

"The youth reflected. He had been used to regarding his comrade as a blatant child with an audacity grown from his inexperience, thoughtless, headstrong, jealous, and filled with a tinsel courage. A swaggering babe accustomed to strut in his own dooryard. The youth wondered where had been born these new eyes; when his comrade had made the great discovery that there were many men who would refuse to be subjected by him. Apparently, the other had now climbed a peak of wisdom from which he could perceive himself as a very wee thing. And the youth saw that ever after it would be easier to live in his friend's neighbourhood."(Chapter 14)