This was not a mere "ruined reputation", but rather a persistent, coordinated mobbing assault big enough that not even a professional PR firm could do anything.
Did he cheat? Likely yes. Did he deserve being banned from marathons? Sounds like it. But did he deserve "the pressure, attention, emailing, even trolling" that he got? No, he did not.
If I were in his position, I would have also tried to sue.