If he familiarized himself with the rules, that kind of build would never even occur to him (which is too bad, but that's a story for another post). Nevertheless, that's what he wants to build. As a GM, my options are:
Pathfinder is a game of rules that are ostensibly balanced. Realistically, there is no way the game can be perfectly designed to maximize fun for all players at all levels of play. It's easy to forget in such a rules-heavy game that the people around the table can change and add whatever they like to make the game what they want or need for a particular character or scenario to be fun.