Married son records his parent’s sex MMS at midnight

Because of a house renovation, a family has to sleep in a single room. At night, the married son and his parents sleep on the bed, and his wife sleeps below the bed. At midnight, the son hears moans but can’t see who is moaning. The next day, he puts on a camera. Later, when he sees the sex MMS, he sees that his father fingers his mother and makes her moan.