Haha! I always figured ghillie tweeds in natural tones were the original camo. He needs a darker shirt though.
Myself, I don't hunt, I'm not in the military, and I don't see the need to buy specialized camo just to fish. I usually just avoid bright colors and wear something in khaki, brown, or olive so as not to clash with the environment. I try to move stealthily and stay out of sight when fishing in close. I suspect that if I'm far away they won't notice me anyway, but if I'm close in and the fish are spooky, they are going to notice my movement before they notice my clothes even if I'm wearing camo.