When David Fajgenbaum was 25, he went from being a monster athlete to death’s door. Fajgenbaum found out he had a potentially fatal disease called Castleman which was attacking his immune system. The doctors couldn’t help him so Fajgenbaum found his own treatment. Now, he’s working on Covid. His story gives us mere mortals inspiration in a time of pandemics, fires and everything else spinning out of control.