After Grampa dies, the family realizes that they do not have the money to give him a proper burial. Much as they dislike the idea, they have no other option that to bury him along the road on their own. Tom points out that workers might accidentally dig Grampa up and think he was a murder victim. He notes ironically, "The gov'ment's got more interest in a dead man than a live one. They'll go hell-scrapin' tryin' to find out who he was and how he died" (Chapter 13). He suggests burying Grampa with a note telling who he was and how he died.
Tom's comment ties directly into the theme of the novel. The same government that will expend huge resources trying to bring the killer of an assumed murder victim to justice does nothing to help that victim while he is alive, along with untold thousands of others, while they are desperately seeking means to sustain themselves and their families.