Jenny's grandmother was an elderly woman who had been through Auschwitz, but escaped with her sense of humor and positive outlook on life intact. She has Jenny drive her on a short journey around town, visiting all the important places from her past so she can say goodbye. When she reaches the whirligig of the whale with Lea on top of the spout, she tells Jenny that someone had told her that after Auschwitz, no one should ever laugh again. But the grandmother saw past that logic, and realized that life is not worth living without the laughter, and it would only let the Nazis win if people didn't laugh and be joyful in life. She said that those who died would want people to laugh the laughs they never got to have, to live life happy and enjoy it. She tells Jenny to be happy, and live life in such a way as to be happy, and not dwell on the sadness in it.
Lea's mother, as well, saw the goodness in things. When Lea died, she didn't know how to go on, but eventually came to think that everything happens for a reason, and even out of this great tragedy there was something to be gained. She wants Lea's death to pass happiness onto others somehow, to make others smile and laugh, just like Lea's life did. She sends Brent all over the country to spread Lea's joyful spirit in the form of whirligigs. She tells Brent, "Let people all over the country receive joy from her even though she's gone. You make the smiles she would have made" (41, chapter 3).
Both women realize that to live life in sadness is a waste. It is better to spread happiness and laughter to others and find the good in even the most evil and saddest times.