Is it permissible to convert the monthly allowance specified by the father into an ongoing charity (Sadaqa Jariyah) after his death, and what are the fields of ongoing charity, and does the charity of the son benefit his father?

A father may take from his son's wealth what he needs, as long as it does not harm the son, based on the Prophet's (peace and blessings be upon him) saying: "You and your wealth belong to your father." The son is also permitted to give charity from this wealth on behalf of his father after his death, as the reward of charity reaches the deceased.