"Hm, are you sure?" Gilbert muses, chewing thoughtfully. Then he laughs, nodding at Elliot's plate. "Guess you'd better keep eating, then. You'll never live it down with the rest of the family if you stunt your growth."

'The' family, not 'our' family, but while Gilbert finds the fact of Elliot being his brother, of that feeling being reciprocal, he knows the same isn't true for the rest of the Nightrays. But that's just fine with him.