Oh yeah, altitude is not a "normal" human environment...your guy probably has stories about perforated ears, crusty eyes, higher exposure to radiation (UV/cosmic) and higher rates of melanoma and prostate cancer, circadian disruption, electro-magnetic exposure, breathing all that canned air and institutional airline food
...
And risks of clots is a known risk when flying...getting a jab that can cause them...has to double if not triple the risk!
And being around Navy pilots I can tell ya most love it dearly and if something develops/happens that if officially reported would have the flight doc ground their ass...they'll skip the official process and treat it on the side (easier on land, not possible at sea)...keeps them in the air but could cause issues down the line if not addressed properly...adding to the accumulation of things a pilot endures.