Uhh...but lack of discipline will break a child's spirit because everyone will dislike them as a human.

My take on the ball situation is...those two children need to figure it out for themselves or they both need to go to their rooms (or own space) and no one gets the ball.
I think that the idea of a parent being so hyper-involved in the day to day disputes between her children is unreasonable. How will they ever learn how to handle things for themselves if they can't negotiate with their siblings?