That was the question, wasn't it? In his determination not to think about it during his fight with Katie, Fred had more or less sounded as though he'd already made up his mind about it. In actual fact, it was simply so much easier to avoid than to face this with George there to back him up. The avoidance was as much of his benefit as for his twin's.
"I don't know," he said after a time. "I shouldn't have to think about this. This isn't something people are meant to think about." It was an assumption, of course, that everything simply ended when people died, but it was one in which Fred needed to believe. The universe couldn't be cruel enough to let people look in on the aftermath of their own deaths. "I don't want to think about it."