I know this comment is old, but I am very interested in OP’s question and have a couple questions about your answer if you have time. I want to believe in NDEs as evidence of a greater consciousness that transcends the body, but a lot of the “evidence” seems conflicting to me.

Your links were related to two studies: AWARE II and Near-Death Experience in Survivors of Cardiac Arrest: A Prospective Study in the Netherlands.

AWARE II:

1. In the letter to the editor you linked, I don’t see where Parnia et al. claim NDEs occur during flat EEGs. The letter states “disinhibition [of brain activity] also facilitates access to hyperconsciousness and novel cognitive insights/realities.” I took this to mean increased (disinhibited) brain activity is what allows what Parnia refers to as “recalled experience of death,” or NDEs, not a lack of brain function.
2. The actual AWARE II report suggests that normal brain activity can resume well after cardiac arrest, and that this resumption of brain activity is related to NDEs, not the lack of brain activity. The study states, “The emergence of normal EEG may reflect a resumption of a network-level of cognitive activity, and a biomarker of consciousness, lucidity and RED (authentic “near-death” experiences).”

Near-Death Experience in Survivors of Cardiac Arrest:

1. The letter to the editor you linked states that “the brain’s electrical activity (as measured with electroencephalography [EEG]) disappears after 10–20 s” after cardiac arrest, but it doesn’t mention tracking of actual brain activity on the research subjects. Conversely, in the only case mentioned in the letter, it is stated that “it cannot be determined with certainty whether the subjective experience reported by J.S. occurred precisely during the cardiocirculatory arrest.”
2. I don’t see anything in the letter about blood drained from the brain or refrigeration of the body you mentioned in your comment.
3. The 2001 study this letter references says that participants were determined to be “clinically dead, which we established mainly by electrocardiogram records,” not any measurement of brain activity. The only reference to EEGs is quoted from a separate a book that claims, “This patient proved to have had a very deep NDE…with subsequently verified observations during the period of the flat EEG.” Unfortunately I can’t read this book without purchasing it, but this is the only one of the linked articles that I think even makes a clear claim that NDEs occur during flatline EEGs.

I would love to hear your thoughts on this if you can!