At the beginning of the book, Tom (the son) talks about how his father would always wait to eat a pig, and by the time he was ready to butcher and eat it, the pig would have died of some disease. By contrast, Uncle John wouldn't save and would butcher a whole pig just because he had a sudden craving for pork. In a sense, both were insane in their own way, one waiting for a promise that would never be fulfilled, the other not having the patience to wait.
Easy stuff. 🙂