Don't put your son through the humiliation of wearing women's shoes! Even if his friends don't say anything, they will definitely be laughing in silence (I do that myself whenever I see a guy wearing women's shoes). I have narrow feet too, but I've been able to deal with this problem without wearing women's shoes.
First, he can get a pair of aftermarket insoles and were them over the factory insoles. Between doing that and maybe wearing two pairs of socks, he should be able to wear a greater variety of shoes.
Also, he should try out shoes that are known to be on the narrow side. My feet are narrow and thin enough that Babolat, K-Swiss, and New Balance are out of the question. Nike Vapors are too big also. Here are some shoes I've worn that fit me:
Prince T22 (personal favorite overall shoe, don't try the T24's because they are huge)
Prince Rebel (slightly narrower than T22 but not as much cushioning)
Lotto Raptor Ultra (I tried the III and it was the narrowest tennis shoe I've ever worn, the IV is supposed to be slightly wider but still narrow)
Most Adidas shoes (the Response in particular is narrow).
Hope this helps.
