What is to be done when a son discovers that his parents are keeping pornographic videotapes locked in a briefcase?

Do not open your parents' private belongings, and advise them indirectly, such as playing materials by some sheikhs about the ruling on these films. If you become aware that they are watching them, advise them kindly and be a good role model for them. Continue to honor them and treat them with kindness, even if they persist in watching forbidden things.