Answer:
He is ashamed because his parents behave very selfishly with the arrival of Mr. Dussel.
Explanation:
"Diary of Anne Frank" is a play that seeks to reproduce the moments lived by Anne Frank's family while they were hiding to avoid being taken to the Nazi concentration camps. Anne Frank's family was Jewish and is hiding in a very small place together with the Van Daan family, who was also a Jewish family.
The two families live with little space and small amounts of food, however, Mr. Frank, decided to help yet another Jew to hide, Mr. Dussel. However, the Van Daan family did not like this idea and they behaved in a very bad manner when Mr. Dussel arrives in hiding. Mr and Mrs Van Daan are concerned about the amount of food now that they will have to feed one more person. This makes their son, Peter, very ashamed.
Peter is also embarrassed when everyone in hiding finds out that Mr Van Daan is stealing the food.