Was he vaccinated?
It was mandated so prob, yes
Are there ANY active commercial pilots who worked during COVID that are not vaccinated?
That's a safe and effective possibility.
I think all airline employees were required to be - I remember hearing about some pushback from those who didn’t want to get the vax but can’t remember the outcome.
Of course, he was jabbed with the mRNA treatment. It was a required condition of employment for all the major airlines including this one.
His career is over now. Hopefully he had the disability insurance coverage.
Did the jab cause this? I don't know. I would go with the odds that it did. But it is impossible to "prove" such things in an individual case. The authorities are counting on that uncertainty to protect themselves from legal and even personal retribution.