When I'm using a CA dealer that I'm unfamiliar with to receive a gun from another state for me, I always ask if they will receive a gun from an out-of-state individual who is NOT an FFL dealer. None has ever said anything but "yes."
The state's interest, apart from collecting a fat sales tax on internet commerce, is apparently that the gun and buyer be run through a CA-DOJ background check (DROS, rhymes with "gross"). Only a CA FFL dealer can do that, so the gun must go to/through a CA FFL.
Have your son find a CA FFL that knows what they are doing and ship it to them. Prepare for sticker shock on the tax and DROS and transfer fees!
