She had the leash that has tied him to this world.
David was fighting with himself every day to not make it more difficult for him and his sister. As long as his mother's property was in dad's hold, he'll always be submissive to him.
Katherine asked him to drive to the Centrum Shopping Mall where she was meeting her friends where he'll be the third wheeler among them, still Katherine dragged him there. It was obvious, if she couldn't make him feel any lower than this then he can't tell what's more to come.
"Kate! You are so late!" One of her friends voiced as soon as we reached the group of three friends.
"Oh! David has come along with you?" Her other friend voiced now looking at David who was standing behind Katherine, looking nowhere in particular.
Katherine elbowed him in the stomach and he coughed out a 'hey!' In their direction. They all responded with a nod and polite smiles.