As a teenager I had the leading edge of a single fin glass-on go into my head while surfing maybe an 8' slabbish wave. I started to lose consciousness underwater, my vision shutting down from the sides as that high pitched whine set in. It slowly came back as I was underwater and when I came up I found my leash-less board right next to me. Felt like I was drunk, my inner ear was mangled. Grabbed the board and hung on like a tick until I got washed to the beach. Driving home I had to pull over. Then the ear started whistling and this thickish liquid started coming out of the ear. The skull was fractured and my ear drum had blown out from pressure on the inside. The liquid was spinal fluid coming through the crack, into my ear canal and out through my blown ear drum. 2 weeks in the hospital. I was surfing a week later. Some people are more durable than others. I have a hard time believing getting 3 feet of air in 3 feet of surf is going to cause a normal person any damage. If so, every water skier and wakeboarder in the world should be dead.
But your mileage may vary. If this is legit I wish him all the best. He's an entertaining surfer to watch. People who engage in contact sports frequently lift weights in a manner specifically designed to strengthen their traps/neck to minimize head snap/brain bounce off the skull. Maybe something more fragile people should consider for even activities like surfing.
I should probably get a brain scan. Not really sure I want to know. The horse has pretty much left the barn at this point.