This individual is not interested in being part of a team
Good god man....you say you are a SNCO....then bloomin act like one. Have you encouraged him to be part of the team...(Remember "The team works"). Have you interviewed him, made him feel part of the team ? Or...have you acted like a complete and utter weak kneeded SNCO and ostrasised him from your unit. Get a grip of your section and do what your paid to do - Lead your men.