My father passed away, and I came to know that he owed debts to many people. Some of these debts are…

My father passed away, and I came to know that he owed debts to many people. Some of these debts are documented in writing, and some are not. If one of my father’s acquaintances came to me claiming that my father had borrowed money from him, but without written proof, and he says he is willing to swear on the Qur’an that my father borrowed from him—am I required in this case to repay the amount if he swears?