I took a closer look at that article -
It appears to be ultimately saying that the confusion over the definition was more about how the condition is identified and defined, rather than what it actually is. I.e. -
The major debate further explained the UK position on brainstem death and helped to clarify why the UK and US positions were semantically different but clinically synonymous.
With the 1995 American Academy of Neurology practice parameters, the differences between the UK and USA brain death determination would become much less apparent.
Pallis noted in 1990 ‘to date not a single case seems to have been recorded, in a reputable and widely accessible journal, of a patient with well documented structural brain damage (from trauma or intracranial haemorrhage, for instance) who recovered brainstem function after fulfilling properly applied clinical criteria of brainstem death’
Brain death is taken as legal death, governed by strict legal definitions that need to be fulfilled. However, it has to be discovered and diagnosed by physicians and machines, who are not infallible. That said, I think incorrectly diagnosed cases of brain death would be extremely, extremely, exceptionally rare.
Ultimately, it once again comes down to being informed and making your own individual choice. What do you want for your end of life decisions? As the neurologist above said there has not to date been reliable evidence of a person recovering after fulfilling properly applied clinical criteria of brainstem death. And yet for organ transplants, there is a 90% success rate. One person can save 8 lives through donation. Some donor recipients go on to live 40 years longer than they would have without the donation.
In the absence of any religious textual guidance (given that the idea of defining brain death and achieving organ donation have only be around for the last century or so) we have to take accountability for our own decisions. The most important thing is looking at the evidence, making a clear decision, and then informing your family or loved ones of your wishes (including, if necessary, what your definition of death/brain death is). This ensures that your intentions for the future of your organs are followed, while also easing NOK suffering at what would be, a most distressing time.