My little brother is in his mid 50s and has been a captain for a major airline for decades. He gets an FAA first class physical every 6 months. A month ago the physical caught heart inflammation and swelling which he has never had before and he was grounded. The doctor suspected the Covid shots. This risk is not just for teens.
There was no small number of Air Force pilots who left the Air Force rather than take the anthrax vaccine over fears that they would become medically unable to perform their civilian job; nobody then (or now, certainly) thought that their fears were baseless.
I hope your brother is able to return safely to the cockpit. If he was compelled to take this shot by his employer, it would be incredibly ironic if it ended his career.
I was in the local ER twice in the last month. More than half the people coming in were there for severe reactions to the COVID vaccine.