I was able to eliminate front brake shudder on my old CX bike by adjusting the toe-in and contact angle of the cantilever brake pads.
If he's only riding road, switching the brakes out to mini-v's are a great option. They will give way more stopping power and have no shudder. I ran TRP CX 9.0's on my canti CX bike for years and they work great, but you have to run the pads super close to the rims.