How does Maria react when Bruno calls his father stupid?

From the text:

Maria's eyes opened wide and she took a step towards him, her hands covering her mouth for a moment in horror. She looked round to make sure that no one was listening to them and had heard what Bruno had just said. 'You mustn't say that,' she said. You must never say something like that about your father.'
'I don't see why not,' said Bruno; he was a little ashamed of himself for having said it, but the last thing he was going to do was sit back and receive a telling-off when no one seemed to care about his opinions anyway.
'Because your father is a good man,' said Maria. 'A very good man.
He takes care of all of us.'