All I can say is WOW! It blows me away that she is able to continue to get away with behavior that is in the sociopathic area of behavior. No wonder that she thinks she is above the law, she is. As for your husband and FiL they must feel that there isn't much they can do, but keep her happy at any cost. I am not sure what you can do to change this. Is there anyway for you to leave the area where you live now. I don't think that without putting some distance between you and your MiL that you can change anything enough to make a difference. You have my deepest sympathy.