WHY DID THE WOMAN ASK THE FAT MAN "THEN IS YOUR SON REALLY DEAD"?DIDNT SHE HEAR THE SPEECH THE FAT MAN WAS GIVING TO THE PEOPLE ON TRAIN? WHY...

In the story, the author says that she asks him
this

just as
if she had heard nothing of what had been said and almost as if waking up from a
dream

To me, this means that
you can definitely argue that she has not really heard all of what he has said.  She
must have heard some of it to know that he had a son, but maybe once she heard he was
dead she sort of got lost in her thoughts.

In terms of the
story, though, it makes sense for her to ask this.  Because what she is really doing is
confronting him about what he is saying.  She is really implying that what he's saying
can't be true if his son is really dead.  He can't have those grand feelings if his son
is dead.

She's right -- once he thinks about it, he
dissolves into tears.

So to me, I don't know if it's
believable for her to say it if this were real life.  But for the story, it makes
sense.