The villainous authority perhaps has it easiest -- he just starts giving orders, jeering at disobedience, perhaps ordering executions. Especially since the principle of the foil probably means he has good counselors, who know better than he does. Then, they can still evade his orders, since he probably doesn't have the work ethic to ensure that they obey. Even in fairy tales -- those as far apart as Snow White and The Water of Life have the royal servant spare the life of the royal offspring against orders. Evil counselors would, of course, mean the plot is politics, until the blow-up.
A heroic one has a harder time. The principle of the foil still means probably evil counselors, who are no doubt certain that anything they do to curb the young idiot is just and proper and keeps them in their rightful places. And the writer has a harder time showing it without making the character look too arrogant for words. . . always a trick.
Especially if the counselors actually are good. There the motives have to be delineated still farther.