He was sadistic and cruel, far more than his own father had ever been. He was without a soul... at least a normal one. Draco wanted to protect her from him. He felt the best way was to push her away from himself so that she wouldn't be sucked into the abyss with him. He refused to see her, and stopped answering her letters. After Dumbledore was dead and he had fleed from the scene that had become much easier.