Based on a true story too, sadly, except it was when we were teens and it was this kid who was constantly making fun of his OWN sister for being fat, even though he was too.
First time I made fun of someone because of their weight, and I kept doing it to him for the years we all hung out, even though he stopped ridiculing her after I tore him up on it one day, and that's when I started putting him down.
Others used to make fun of her also, but I confronted them on it the day before, and that was the end of that.