Nick’s shaking inside while asking his questions. Ever since seeing his grandfather in the clearing, he’s been struggling with his emotions. Having Tris around is making things more difficult to deal with. He doesn’t want to scare her, but keeping from blowing up and screaming at Draco is physically exhausting.
It’s clear to Nick that King Draco abandoned the Kingdom, forcing his father to take over the throne sooner than expected. That has to be why his parents wouldn’t talk about him. It’s probably the same reason Granny Nora looks so sad every time she mentions the man she loved.
Nick is livid, his hunger replaced by the growing rage in his stomach. A man he believed to be dead, who he looked up to and regretted not getting to meet, turned his back on the Kingdom and ran off with the dragons. No wonder his family hates them so much.