Crowning Moment of Heartwarming: Adam gets annoyed with Kyle's attitude near the end of the film. But while waiting to go into a final, roll-the-dice surgery, he visits Kyle's house. In the bathroom, bookmarked and dog-eared, he finds a self-help book entitled "Facing Cancer Together."
Not only this, but you realise he's been doing his best to actually follow the book; one of the sections is labelled 'don't become overly emotional in front of your friend', which is what Kyle has been trying to do for most of the film. Rather than break down, he's been trying to encourage things like talking to girls and taking him out.
After Adam has a breakdown the night before his surgery, he calls Katherine and tells her he wishes she was his girlfriend.
While having a meeting with his psychologist, Adam mentions he doesn't call his mother because he sees her as a annoying smotherer. The psychologist defends his mother telling him "She has a husband who can't talk to her and a son who won'tnote Her husband has Alzheimer's . This gets to Adam and he finally decides to return his mother's phone calls.
Adam's entire relationship with Kyle is this. Kyle attends the funeral of Mitch with Adam, and after Adam has his surgery, he stands right beside Adam's parents to hear the news of how it went.