Tom is Douglas's ten-year-old brother. Tom is not in the same position as his brother, because he is not yet truly cognizant of his own mortality. They both share a love of summer magic, but, unlike Douglas, Tom never has to question that magic. Tom provides a unique perspective. He and Douglas often partake in the same activities, but while Douglas is forced to evaluate them in terms of the bigger picture that is slowly becoming critical to him, Tom is free to evaluate things on their own level.
Although he is younger than Douglas, Tom sees things that his brother does not. Tom senses people's emotions extremely well, and he understands Douglas pretty well, even though Douglas is often slightly confused by Tom. Unlike Douglas, as the summer goes on Tom does not draw connections between the events. He continues to live completely as a child, and yet sometimes he thinks of things that none of the older characters come up with. Tom is a perfect example of the creativity of children. Because he lacks the larger framework that Douglas is struggling with, and that adults have fully in place, Tom is not forced to think within that framework. Tom is able to think things that would seem perfectly ridiculous to the other characters but to him seem completely reasonable.
Tom is also very kind and content. Many times life can be wonderfully easy for little kids, because they are happy living each day on its own terms, and Tom goes through summer with hardly a worry. It is not that important things do not affect Tom but rather that he does not worry about what cannot be changed, unlike many adults. There are a few events in the summer that have a great impact on Tom, but they do not cause him to re-conceptualize the way he understands the world.