A mechanical engineer who worked on the f-18 fighter jet program for General Dynamics saw the ‘89 doc

For some reason, engineers can be the most gullible victims of supernatural cons, usually at a more mature age. Perhaps a subconscious reaction to a life in the no-nonsense world of reason and numbers, I don't know.

found Chang, and trained under him for a decade before writing that book to tell the story to the west, like the video attempts to.

I found books on Chang with google, and also on the practice, i.e. mo pai nei kung. The ten years of training give his account weight, if legit.

scientists

Some scientists are also gullible, if James Randi is to be believed, what he probably is.

None of the debunks work

Not sure if I would trust my own eyes if I had met John Chang in person.

Human potential grows by magnitudes when you accept the validity in what is demonstrated by Chang and others.

Acceptance is independet from the demonstrated human potential. If I could set newspapers ablaze with bare hands or heal tinnitus I would give a damn about what other people think. To John Chang's credit, he apparently gives a damn about that.

and thousands of years, Traditional Chinese Medicine was able to “stumble” on some real cures?

Stumble? They researched it systematically. They even kept the records of what did NOT work. That's patently scientific, even if you don't ignore the fact that they were not interested in researching the underlying physics or neurology.

That's what makes the whole thing somewhat plausible.

(Why haven't doctors researched this, people may ask, if legit?

Perhaps for the same reason doctors have not researched medical cannabis. I met with a rogue doctor's encounter/alumni group of cancer- and rheuma patients for political reasons, without expecting much from that. Un-fucking-believable. Most of them had resorted to oil and reefers as a hail mary pass, in the face of more or less certain death. Results within days. And a dealer-friend of mine showed me a video recorded by an epileptic customer and his mother who anointed him on the chest, what stopped a hard seizure (think Pris' final moments in bladerunner) in ca. 20 seconds. The most stunning and undeniable, personally witnessed, results-within-in-minutes account would dox me, but cannabis as medication is realrealreal.)