Before heading off on his road trip, Chris gives Walt an expensive telescope for his birthday, to show his thanks, and promises to call the family frequently.
Chris and his father do not exchange affections, but express gratitude in gifts, underscoring that their relationship is based on things, instead of love.
After Chris returns from his cross-country trip he is withdrawn and cold towards his family because of information he uncovers while visiting family friends during his journey. Chris learns that his father carried on an affair with his ex-wife Marcia, having a son with her, even after he had already settled with Billie. Feeling betrayed, Chris hides his knowledge of his parent’s secret.
After learning the truth about his parents, and his father in particular, Chris feels betrayed. Yet the secret hate Chris harbors is also a betrayal of his parents’ love and trust. Chris’ unwillingness to forgive is a severe punishment. Chris’s rigid moral beliefs are at once noble and punishing, and show no leniency toward the fact that people are humans and make mistakes.
In July 1992, two years after Chris disappeared on his post-college ramblings, Billie awakens in the middle of the night to the sound of Chris’ voice, shouting for help.
Whether real or imagined, Billie’s experience communicates her deep love for her son and anguish at not being able to care for him. Whether Chris really was thinking of his mother at this time is of course impossible to know, though his realization (described later in the novel) that happiness must be shared does show that he was ready to give up his solitary lifestyle.