What is the ruling on someone who swears an oath over another person to punish them or control them by making them do something?

It is a Muslim's right to fulfill his Muslim brother's oath if the latter swears upon him to do something that is not obligatory, or to refrain from something that is not forbidden. This is on the basis of desirability and recommendation, due to the Prophet's (peace be upon him) saying: "The Messenger of Allah (peace be upon him) commanded us to do seven things: ... and to fulfill an oath." It is desirable for the person in question to fulfill his brother's oath, provided that it does not result in harm or hardship. Otherwise, hardship is removed and harm is alleviated. If the oath is not fulfilled, then the one who swore the oath must expiate for his oath, and the one upon whom the oath was sworn bears no responsibility.