Why does Haoyou have animals on his jacket?

Hayou's mother embroidered the animals on his jacket. On pg. 14, we learn that his mother is going to an embroider a tiger to chase away his bad dreams. He's had some of the animals since he was a baby and has given them names. When he grows out of a jacket, his mother removes all of the animals that have represented things over the years, and she sews them on his new one.