I have looked at the replay of Zo's injury multiple times, and it's just freaky, hard to believe that the contact we all saw caused so much damage.
Perantes from UVA actually had a similar, but less serious injury recently, but it was patently obvious from the replay that he took a major blow to the head (concussion and broken nose at the bridge), but he is back playing already. Of course he didn't have surgery, but based on the blow, I would have guessed he had a much more serious concussion than Zo did.
Just goes to show that we can't judge these sort of things based on how they appear.
Having been an athlete who had multiple concussions, and as a participant in the Boston U. CTE program, my advice to ANO would be to listen to the doctors, and don't rush back. He has the rest of his life ahead of him just like Becca Wann does.