Is there a reason we should care about his belief regarding this? Putting aside that smart people in one realm are often quite irrational outside of their expertise, e.g. Isaac Newton being super dedicated to alchemy, Jack Parsons at JPL believing he could summon demons, there is also a quite obvious limitation to this line of evidence. I have very good reason to believe I'm going to survive the next five minutes. That doesn't mean I'm going to "survive" in the sense that we care about regarding why religions draw people in, that is, even conclusive proof we survive past bodily death doesn't make us immortal. An immaterial soul that lingers to experience more stuff for another 20 minutes hardly makes a difference, but even if we can conclusively prove near-death experiences are real, that's all we'd be proving.
Same thing with the ontological argument. Even if you can convince yourself the universe must have some kind of intelligent creator that made it on purpose, that does not imply this creator has any kind of human-intelligible personality and monitors or cares what we do, let alone that it must be the Christian creator or any other specific religion's idea of what a god is. Ironically, my wife put on just this morning an episode of Rick and Morty in which Morty gets trapped in the Roy game and Rick has to go in and convince everyone they're in a video game and are really part of a larger reality, which was meant to be a parody of religion. That is, their universe truly did have an intelligent creator, but they were NPCs in a video game and the larger reality is they were really a 14 year-old boy in the real universe. We have no particularly good reason to prefer a priori Christianity versus Hinduism versus we're all 14 year-old boys trapped in a video game just because we're convinced we have a creator and some part of us survives death in this particular simulation. Notably, the real Morty is still going to die in the real world.