Vinci, after returning from hanging out with his cousins: "I wanna be with my guys. I wanna be with my grand-brothers."
I asked if he meant Grandma and Grandpa, but he said no; he confirmed he meant his cousins. It seems like a pretty systematic word for that.
(Earlier, he kept referring to them as "Eddie's cousins"; I said "They're your cousins too!" and he said "Huh?")