Yogurt, is good for clearing thrust in a women, smeared down below, so I guess that it should work the same way for a man if swallows it, but first he needs to swill it round his mouth then swallow.
Good Luck
He may develop thrush, an oral yeast infection. Unlikely though, but possible. And it is treatable, so even if he gets it, he'll be given a pill or two and be fine. So no big worries.