The fact that Peter might be dead never crosses the Just's mind. It's just not something that can happen: Peter can't be dead if the rest of them are alive, which isn't logical but it's just how things are. He doesn't know why.

Edmund nods, however, at the suggestion. "Well," he says, pushing the apple away a little. "Could it be that he just...went home?" He doesn't know how going home works, but he does know it's not altogether voluntary. Peter would never leave his family. It's just not something the High King does. But the suggestion can't be overlooked.