Is it permissible to swear by someone's mercy, such as saying: "Do such-and-such by the mercy of your father or your mother"?

It is permissible to swear by Allah's mercy, but it is not permissible to swear by the mercy of a created being, because it is created, and swearing by a created being is forbidden. Accordingly, if the saying of the speaker "by your father's mercy" intends Allah's mercy upon his father, then it is permissible. But if he intends the created mercy of the father, then it is not permissible.