I have some proof here that there's no afterlife

[Sword of Christ]

But again, people who experience NDEs are NOT dead

Medically speaking they would count as being dead everything would be flat-lined on the charts. It's just that they can be revived back to full physical function while a 4000 year old Egyptian mummy can't be that's the only real difference.

and not every near-death person experiences NDEs.

Do you remember any of the dreams you had last night? The brain may just act to filter out NDEs in much the same way in a kind of selective amnesia. One thing people who remember there post death state report is that they remember everything they can view their entire life. So what the brain essentially is is a filter it limits an organism to what it requires for survival in the physical world. Once the brain shuts off you're back in as state of pure consciousness without the filter.

If death were simply a different grade of consciousness, then it would follow that EVERY person near death would have a NDE (because everyone is conscious and everyone dreams).

Everyone dreams but we forget more than 4% of them so that just demonstrates the point.

There doesn't seem to be a difficulty in translating the NDE - people who claim to have had one always go into great and mind-numbingly dull
detail about them, while people who were near death and did NOT have the experience report - nothing (this includes your Humble Narrator). There seems to be no middle of the road.

It can still just be a form of amnesia in that you're not intended/designed to remember your non-physical state while you're still alive. When you're dead you will remember everything without the filtration cap of your brain. People who remember their postmortem experience being the exceptions. What they recount fits with the concept of the brain being a filter of a stream of consciousness.

Quite a long time ago, Carl Sagan wrote a terrific essay regarding NDEs. I don't recall the title of the essay (and can't be arsed to get up and look for it), but you'll find it in his book, 'Broca's Brain'.

I don't think he would have taken the concept of the brain being a filitrator of consciousness seriously but only because he was presupposing materialism to begin with. There is no reason why it has to work the way he believed it to be as nothing in science would particularly support it.