It was impossible to keep her laughter under control after being shocked by Oliver's response. Evidently, a lot more had changed in their home when she was away than she realized. Perhaps it wasn't the right response to have under the circumstances, but no one had ever claimed Hermione was a great mum. Or even a halfway decent one. Maybe better mothers wouldn't laugh in such a situation at what their child said. She really didn't have the first clue.