A boy comes to love and understand his brother, a trans boy, as the brother transitions.
The narrator first observes that his “big sister” isn’t happy. He tries to do cheery things, but nothing works. Finally, he learns that the person he thought of as his sister “wanted to be my big brother Jon…. Now I have a big brother, Jon.” It may be unclear to young readers whether there is a third sibling named Jon whom the sister simply wanted to imitate; adults may still have to explain what it means to transition. Once readers get past that, it’s also unclear what made the sibling want to be Jon. Sometimes children use phrases like “I want to be just like you” when they mean things other than gender. Nevertheless, what comes through clearly is that Jon is much happier being Jon, and the narrator thinks their brother is “awesome.”
As a book for explaining what it means to be the sibling of a transgender boy, I prefer Jack (Not Jackie), although My Awesome Brother has its heart in the right place and could be used as a supplementary story with some additional adult explanation.