How is Grandfather's reaction different?What does she mean when she say to her son that he is dressing up like a puppet on a string without caring what it really means?Why does she find both her husband and her daughter-in-law foolish?

Grandmother is not a supporter of the Nazis. She feels she did not raise her son to be a puppet for an evil fascist regime. She says her son is no commander: he simply does what he is told to do by Hitler. Grandmother knows what the Nazis and Hitler want people to believe but she will have none of it. Grandfather is more supportive of his son. 

She meant that she didn’t want her son to become out and become an Nazi soldier (commandment