"You coming to tuck me in?"
"Yeah, something like that."
Their relationship was strained, and Luke knew that. But now, Nick was dead, and he wasn't coming back. Not as a person, not as a walker. He was just gone. And Luke, he couldn't even fathom what to even think right now. He couldn't process his thoughts, he couldn't process his new feelings. But most of all, he felt numb. It was like he couldn't even feel sadness at the moment, and that made him question his loyalty to Nick.
They'd been friends around twenty years or so... So why wasn't Luke able to cry about Nick's death? Shouldn't the loss of a friend bring about tears and sorrow and sadness? He should feel horrible that his best friend was dead, and it was partially his fault. Luke hated himself right now. Was he really that selfish? Was he even Nick's friend?
Or maybe it wasn't Luke, maybe it was the world that they lived in. He had become so hardened by the new, cruel zombie apocalypse world, that maybe, he didn't know what sadness was anymore. Sure, Nick was dead, but death had become part of the new life. People died everyday, and hell, Luke lost people all the time. Maybe dying was the new norm. But Luke didn't want it to be that way.
He just wanted his friend back.