What is the ruling on hitting a sister who shouts in my mother's face and makes her cry?

"Hitting is the last resort and should not be used directly, but only after exhausting admonition, reprimand, and boycotting. If the sister does not respond to advice and reprimand, and is boycotted, and does not stop harming the mother except by hitting, then she may be hit when she harms the mother, provided that the face and vital organs are avoided, and that the hitting is only as much as needed and does not lead to harm. As for hitting after the harm has occurred, it is not permissible because it falls under the category of discipline, and the authority to discipline is established for the Imam or his deputy, or a guardian with special authority. The Hanafis held that every Muslim has the right to change evil with their hand while the transgression is being committed."