Dicey’s youngest sibling, Sammy, is known for fighting. Or at least he was. Once he gets to Crisfield, he tries to be a perfect student because he feels guilty for letting Momma down with his behavior. While most families might be thrilled at this change in a previously rowdy kid, Gram and Dicey know that Sammy’s not being true to himself. After his school conference, Gram catches Dicey up on the deets, and Dicey puts it to Sammy like this: "Gram said you’re being an angel at school. Except you don’t fly" (6.12).
Well that doesn't sound good. Sure, Dicey and Gram don't want Sammy fighting. But they also don't want him to become a zombie either. The kid's gotta assert himself, right? So when he gets in trouble for fighting with a kid named Ernie, Gram and Dicey are content to let it slide: Gram "didn't seem to mind the punishment of not being able to ride the bus for a week; she agreed with Sammy that that was fair." Later, they'll learn just why Sammy was fighting—to defend Gram's honor. So it appears that Sammy's acting out isn't really acting out anymore. He only fights when provoked (not that that makes it okay).
The whole fighting debacle also indicates that Sammy views Gram as part of the family, as someone worth defending as one of his own. We have a feeling that when it comes down to it, Sammy's gonna be just fine.