Character Analysis
Geoffrey is Jack's older brother, who seems to be the only one in the family with a sense of responsibility. He goes to Princeton, which feeds Jack's fantasies about a better life:
I… told strangers who picked me up on that road that I was a Princeton student coming home for a visit. (21.1)
Like Geoffrey's dad, he doesn't really know Jack's situation with Dwight. Unlike Geoffrey's dad, he actually seems to care about it, and encourages Jack to apply to private schools back east. He even helps support the family when Dad goes nuts by "working at Convair Aeronautics." (31.5)… perhaps showing hints that not everyone in Jack's family is a complete screw-up.