Only Augustus could find the humor in their son's actions. Maybe he didn't realize that Oliver was angry. Or perhaps more likely, he understood perfectly but his personal experience with his own three sons meant that he wasn't impressed. The former Unspeakable laughed his loud belly laugh when he saw the young wizard glare in his direction. Since their conversation days after they first arrived when they thought they were alone in the kitchen, Augustus and Oliver had developed a good relationship. Sometimes Hermione thought that despite being the oldest person in the house, Augustus was just an overgrown child. She assumed that was why they were able to make each other laugh.