Ketamine is sometimes used for surgical anesthesia when people are found after car crashes, and it definitely regularly causes hallucinations of precisely that sort, which is the reason it is not the most favored anesthetic. If your dad indeed received ketamine, I think that's a very likely explanation. There is also a theory that near death experiences sometimes result from a release of natural DMT.
I am way more inclined to believe in the ultimate benevolence of the universe than most people here (which means that an afterlife or something like FAI resurrecting all dead is not as unlikely as the God of Abraham), but still think that most NDEs are explainable in terms of neural activity.
Not sure I'm parsing your parenthetical statement correctly, but a universe ruled by the Abrahamic God is a universe I definitely wouldn't label as "ultimately benevolent", rather the opposite in fact.
I was on Reddit today, and I came across (this link)[http://www.reddit.com/r/AskReddit/comments/eyiat/for_those_of_you_who_have_died_and_been/]. One of the things I've seen on this site that's bothered me is the exclusion of personal experiences in deciding what a person should or should not believe. I know that less wrong is mostly atheist, and I wanted to hear less wrong's reaction to descriptions of experiences like these.
For example, my dad was in the hospital 5 or 6 years ago when a truck came across an icy road and hit him head-on. His most vivid memory from this is a dream he had when he was in the hospital. He was in a pool of water with my mom, and they were both naked (they were underwater, but didn't need to breathe). He remembers that at the end of this pool, there was a bright light that he wanted to head towards. He began to swim that way...and here, I don't remember what happened, but he was unable to reach the light for some reason.
Such stories seem to be common for people who come close to death, and for a community based around rationality which seems to consider the likelihood of life after death as slim, I just wondered what your reactions are. My reaction is that such experiences are explainable in terms of neural activity, but that doesn't necessarily exclude the possibility that these are descriptions of experiences of an afterlife. I'm not convinced by them, but I do consider it to be possible.