The correct answer to this open question is the following.
Unfortunately, you did not mention the name of the book, the name of the story, or the name of the author so we can look for it.
Without this information is so difficult to help you answer the question.
However, trying to help you, we can use our knowledge on the topic to comment on the following.
It is probable that you are referring to the novel titled "The Rules of the Game," written by American author Neil Strauss. The story was published in 2007.
In that story, the mother plays a key role and she has a personal belief that sums up her philosophy in life. So the mother's statement "Strongest wind cannot be seen"contribute to the development of the theme because the mother, Mrs. Jong thinks that the most powerful things in life cannot be seen, as in the case of the strongest wind. She called this "the art of invisible strength." For Mrs. Jong, this means that people have to have "self-control of their actions." For her, self-control has the power of the strongest wind.