Does lying really make everything better?

Throughout the novel When the Emperor was Divine by Julie Otsuka, a reoccurring prevalence is the subject of lying. I can understand how lying can sometimes make a situation look significantly better than it really is, but what is the point of it can not improve anything?
There are several different instances where the Japanese-American family the novel is centered around using lying as a mechanism to display the irony of a situation well. I think people often feel by lying to themselves, instilling hope and optimism it makes one feel mentally better. For example, on page 29, the family is on their way to an internment camp where the Japs were sent shortly after Pearl Harbor. The young daughter's little brother says to her according to Otsuka, "Do you think we'll see horses?" "I don't know," said the girl. She remembers reading here about wild horses. The paragraph then says, "If a cowboy needed a new horse, all he had to do was go out into the desert and get himself one. So she told the boy that they probably would." On page 30, the boy asks, "How many do you think we'll see?" "Quite possibly, eight." Why lie about something as trivial as horses? In this book, the wild horses represent freedom, something the family won't have for another three years. The boy grew up with horses and being in the horse stalls, so for him to ask that instills a sense of normalcy and familiarity in him. By his sister lying to him and reassuring him that horses will be seen allows that innocence to remain for the boy. It gives him something to look forward to on their little "adventure."
Another form of lying is on page 42. The family receives a note from their father. The note says, "I am in good health and hope you all are well." Now, I highly doubt that the father was not tortured or stricken down when he was taken in and arrested. Being the man of the family, the father of course wants to reassure his family he is okay because he does not want them to worry about him. The lie also becomes evident at the end of the story when the family describes the event of their father finally arriving home. Because of his appearance and his evident change in demeanor ,on page 132, Otsuka writes, "He was somebody else, a stranger who had been sent back in our father's place. That's not him, that's not him. He uttered our names, but still we could not be sure it was him." The reader is aware of the changes that will occur, yet the children are not. This shows that lying is a form of this horrible story and through lying in an optimistic manner, maybe this is what instilled hope in the family and kept them going.