"How long ago was the apocalypse for you?" Sam said. "He said it was five years ago for him. I know you're ahead of me, so maybe we can figure out how much farther ahead of you he is."
Sam understood the sigh of relief, although having his concerns validated was less than comforting. He wanted to believe it was just a personality change, that nothing was actually wrong, because that would have been easier to handle. But it was never that simple, not for them.
"He seems..." he trailed off, searching for the words. "I don't know how to explain it either. But... I've heard him, at night. You must have heard him, too."