Who knows? Because you seem like you'll break otherwise, probably.

[His tone is flat, as he follows Xion's instructions. He doesn't entirely know how to answer her, when that's not the sort of thing people tell him—he's never needed the reminder.

When you're not living for yourself, giving up isn't an option.]

Living is hard work. Harder work than being dead, at least. It's easy for the dying to tell those who survive not to give up.