Why does bundled up woman ask most important question?

To me, her question, and the answer it gets, show how deeply war affects people.

The fat man has been talking so much about how glorious war is.  He has been saying that his son was proud to die for his country.  He seems to be at peace with the fact that the war has taken his son.

But then the woman asks her question and he falls apart.  It is as if he had not really been understanding that his son was dead.  When she asked the queston, the truth was forced upon him and he was no longer able to keep up his pretense.

So her question forces us to think about what war really means -- it really means that people we love die.