Have you tried physical therapy? First, a therapist needs the reports from any imaging he has had and they need to know if there is any instability in his neck. They have some treatments to block pain which I've done myself. I've had spine surgery at Mayo, but before coming to Mayo, my PT bought me some time when I couldn't find a surgeon who would help me. There is a "cold" laser (low level), and a Dolphin Neurostimular which sends current between 2 hand held devices that blocks the neurotransmitters than conduct the nerve impulses. Both of these measure feedback during treatment and adjust accordingly. My PT would do that across all the nerve roots in my neck. She also manually treated the muscles spasms which are also a source of pain when they move the vertebrae around increasing the pressure that can cause a pinched nerve to get worse. It's also possible that the pain can be coming from someplace other than the neck, for example thoracic outlet syndrome. I have this and it is a compression of nerves and blood vessels inbetween the collar bone and rib cage. It's a muscular tightness from the neck to the chest and it causes arm pain and weakness. I've had both a spine problem and TOS together. Physical therapy can also help TOS. Computer usage usually makes TOS worse because it's a positional problem and incorrect posture with forward head and shoulders makes it worse as does stress. A neurologist can evaluate to see if there are other places that nerves might be pinched. He could also have something like carpal tunnel syndrome with nerve compression in the wrist (and I've had that too). I am getting better with therapy and exercise, and my PT also does myofascial release work that stretches out the tight fascia that binds everything together. This helps get things back where they are supposed to be. Posture is very important. FYI, usually a surgeon decompresses a nerve. It's important to figure out exactly where the pain is coming from in order to try to fix it. In his case, there may also be surgical scar tissue that can be contributing to the pain. I wish him well in his recovery from knee surgery.

Here is some information about TOS . https://www.mayoclinic.org/diseases-conditions/thoracic-outlet-syndrome/symptoms-causes/syc-20353988

Here is some information on carpal tunnel syndrome. https://www.mayoclinic.org/diseases-conditions/carpal-tunnel-syndrome/symptoms-causes/syc-20355603