Hopefully he's strong enough that going to a good school with a good institute will be an adequate substitute. Of course there are schools out there that offer just as good or even much better of a secular education. To me it was the very good education plus the overlay of gospel principles, and being with tens of thousands of like-minded kids, that was BYU's real distinguishing factor. Perish the thought, but I do have nieces at the U who swear that the institute there is pretty outstanding and gives some of that being with like minded kids part (though I don't think the U's undergrad education holds a candle to BYU's; call me biased).

One other less attractive option, if it's BYU or bust: I think it may be worth looking into if he can take classes at the BYU Salt Lake Center or LDS Business College, then apply to transfer. Or maybe he attends one of the Stanfords, UCLAs, Michigans, etc., of the world and doesn't look back. But I feel for him.