Is the intercourse that occurred after the cessation of bleeding and performing ghusl valid, or is the blood that appeared after intercourse considered menstruation?

There is no harm in a husband having intercourse with his wife after her bleeding has ceased and she has performed ghusl (definition). The blood discharged after the completion of her regular period is not considered menstruation; rather, it is blood due to an ailment or dysfunction, unless it appears fifteen days after her period of purity, in which case it would be considered a new menstruation.