That's about as fair as it gets. And he was fortunate enough to have bystanders to convince dudes it was over (although about 4 swings too late).
And he was the one to walk back, swing first and rescalate it. So he did ask for it. Still feel a little bad though. Got absolutely rocked. There's definitely gonna be some lingering effects or maybe longlasting. Chronic headaches at the least.
On another note, these fight vids man...