First, one must examine how Gene behaved before Phineas died. Gene was jealous of Finny and had anger issues so much so that he eventually wounded his friend for life! This novel discusses the issues that many teenagers face as they are growing up. Once they learn from their mistakes, they act better and more maturely. At the beginning of the novel, when Gene is reflecting back on the tree that was the instrument he used to hurt his friend, he says,
"This was the tree, and it seemed to me standing there to resemble those men, the giants of your childhood, whom you encounter years later and find that they are not merely smaller in relation to your growth, but that they are absolutely smaller, shrunken by age" (14).
This shows how he looks on the incident years later and how things seems bigger and more blown up when you are in them than when you are looking back on them.