Old Man Rhythm (1935)

Rich John Roberts, Jr. gets reports that his son, Johnny, is falling for a gold digging blonde at college. So he enrolls as a freshman to try to steer Johnny towards the girl he'd like him to marry. He hits upon the idea to have the blonde believe he lost his business, by writing a letter instructing his partner to wire him that his business went broke. But he gives the letter to a school official who forgets to mail it.