I'd add the weight first, which will certainly decrease recoil proportionally to the amount of weight added. As for having the barrel Magna Ported, that would be my last choice. Not only will it significantly increase the muzzleblast, but it also effectively shortens the barrel to where the first port is located, which will cause you to lose muzzle velocity. If adding 1/2 to 1lb of weight still doesn't make the recoil tolerable, I'd consider buying a rifle chambered in a lighter recoiling cartridge. Some people are just more recoil sensitive than others, and the .30-06 might be a little too much for him.

Mike