Until we know (if we ever do) the actual circumstances, we can't really make assumptions. For a start, did his dad do the driving home. or was there someone else to drive?
As far as "mitigating circumstances," I'm not so sure about that. Seek medical advice (plenty of that around) and seek another mechanic. If medical advice is "go home" then maybe, but the rider should still be disciplined for not riding in the meeting (I would expect a 28 day ban).
But, as I say, let's hear the truth of what actually happened.