You see it as whining, I see it as talking about what's bothering you and searching for solutions. So your mom does know he's abusive, she just doesn't know a way out either. Even though she yelled at you or was mean to you, try to be patient with her. During the day they are gone, do something for yourself--even if it's something like painting your nails or baking your favorite cookies. Don't forget to keep telling yourself how wonderful you are!