What is the ruling on one who steals and practices sorcery to incite discord among family members, and is it permissible to inform the family about him?

This action is forbidden, especially if it involves sowing discord among people. He should be advised and reasoned with in the best manner, and enjoined from evil. His family should not be informed unless it becomes necessary to prevent his corruption. The preferred course is concealment, based on the Prophet's (PBUH) saying: "O Hazzal, had you covered him with your cloak, it would have been better for you." This applies to someone who does not openly commit the sin. As for someone who publicizes it, it is permissible to expose him and disclose his affair so that he and others may be deterred, because Islamic law aims for concealment for those who do not publicize their sins.