What does Grim call Gram in Philbrick's Freak the Mighty?

"Grim" and "Gram" are the special nicknames Max uses for his grandparents, but those aren't their real names, and they aren't the names that the grandparents call each other.

Although Grim rarely addresses Gram with a name, when he does, he calls her "my dear." This happens two times: once in Chapter 14, when Grim is comforting Gram while they are both worried about protecting Max from his father, and again in Chapter 15, when the family is celebrating Christmas and the normally reserved Grim is feeling more affectionate than usual.

Here's that first instance, from Chapter 14:

"Next thing, Gram is crying, and you can tell Grim is trying to make her feel better, going, 'There, there, my dear. I know, I know. There, there.'"

Here's the second instance, in Chapter 15:

"Gram says, 'How can you tell such lies on Christmas Eve?'

'I'm telling tales, my dear, not lies. Lies are mean things, and tales are meant to entertain.'"

It's worthwhile to consider what the characters call each other, because that reveals a lot about what kind of people they are. For example, Max calls his best friend by his nickname, Freak, though Freak's mother calls him by his real name, Kevin. This helps us understand that Freak's mother wants to see Kevin as someone normal and respectable, while Max accepts Freak for the unusual personality he's cultivated for himself.

Getting back to Gram and Grim, then, the fact that Grim calls Gram "my dear" shows that he really is a tender-hearted man, despite how reluctant he usually is to show it. And further, the fact that Grim usually calls Max by his name, even by his full name "Maxwell," shows that Max's relationship with his grandfather is a bit stiff and formal--but then on a rare occasion, Grim called Max "son," which made Max feel surprised and happy because of how affectionate his grandfather was being.