Well, if the guy has basically indicated that he knows best, then leave him to that. Solves your problem and solves his. C'est la vie
If he's observant, he'll notice he's not improving and then take steps to either correct or find another avenue to pursue. I think the only issue would be around safety / cranking things, should tempers flare. It kinda goes hand-in-hand with this sort of behavior / personality.
Thinking of it historically, there have always been "folks who pay the rent" and "actual students of the art". Isn't there some kinda parable about sheep and goats?