I'm going to go ahead and say, he got the vaccine and had issues with it.

Likely got his 1st or 2nd booster. Likely had heart inflamation or some sort of brain inflamation from the first 2 or 3 doses. Kept getting injected and made it worse.

Those spike proteins are nasty. The more people inject of that stuff the more they are going to have inflammation and a potential life threatening injury from it.