This is an author I started reading in college on the recommendation of a friend (or more) who was a huge fan. I read myself through the Riverworld series and a couple of short story collections. I won't say the entire Riverworld series was worth reading, but at least half of it was. I don't know if I've read the entire series through again since then, although I do reread the short stories periodically. And we watched Riverworld miniseries on a few years back.
Whatever the afterlife is, Riverworld, or no, I hope he finds happiness in it as fair recompense for the hours of entertainment he provided.