The state’s child protection agency has found that the family of a 9-year-old Brockton rapper did not abuse or neglect him by allowing the boy to star in several videos posted online showing him in club scenes and simulating sexually suggestive activity with women. The controversy surrounding Luie Rivera Jr., whose stage name is “Lil Poopy,” began in February, when Brockton police filed a child abuse and neglect complaint against Luis Rivera, the boy’s father. After a month of investigation, the state Department of Children and Families has closed the case without taking any action against the father. “After a...