Does fear of the unknown (i.e. what happens after death) fuel human belief in a God?
Fear of the unknown can fuel any belief. Fear of what it would mean for my own life if a God truly existed could fuel a belief in atheism. Fear of persecution and ridicule could fuel belief in whatever is the accepted social norm wherever you are, be that humanism, Islam, Christianity, or anything else. Fear is powerful motivator, but it is never the right reason to believe in a thing.