They don't. They first see a tunnel of white light, and then they dream up all sorts of whacked-out hallucenations including the usual: Dead relatives, Jesus, angels, etc. One guy in Philladelphia thought that he saw God and reported that God looked like Ronald McDonald.
The unusual thing is that the strongest beleivers in NDE are also people who tend to be fairly pious. Truly faithful people would understand that actual evidence of God or the afterlife would invalidate the true wonder of faith, and reduce us all to puppets carrying on a cruel play.