Sheridan has a good idea there. Whichever is closer to you either Cabelas or Bass Pro Shop. But if you want to buy boots local Herman Survivor boots are pretty good. They come in a variety of styles depending on how much insulation you want or if you want them non-insulated. And they won't break your wallet. Another choice is an all rubber boot like Muk, LaCross and others. I'd try to get it out of him what type of boot he likes or just take him out and tell him to pick a pair out for his BD.