B.P.
I know Stride Rite is a great place for wide, xtra wide kids feet, they do a good job fitting the feet for the right size/width. (both of my boys have had the same problem) They are more expensive though, so if you don't want to spend the extra there, get his feet sized properly there then you can go to Shoe Department or some other regular shoe stores, and look for New Balances, usually no more than $30 in the right size and wide widths. You can find them online in extra wide also. I always bought New Balance for both of my boys.