In The Lone Ranger and Tonto Fistfight in Heaven, what is the significance of the character Thomas-Builds-the-Fire?

In many ways, Thomas-Builds-the-Fire is a representation of how the typical American perceives the Native American culture. His use of storytelling makes him easily connected to the oration traditions of the Native American people. However, Alexie uses certain sections of the novel to show the power of story-telling, which heightens Thomas-Builds-the-Fire's value as a character. 
In the novel's tenth chapter, "The trial of Thomas-Builds-the-Fire," Thomas tells a story of how he fought and killed many soldiers in a battle in the 1800s. The novel's narrative is set in the later 1900s, so Thomas would not have been alive much less killed men in battle. His story is convincing enough for the court and Thomas is convicted of crimes which are described in his story. Alexie uses Thomas to show how powerful a story can be, and this can be tied back to the values of Native American oration, which was a highly valued cultural tool for instruction. Thomas continues to be a source of instruction and support for the main character, Victor, throughout the novel. 
Thoms-Builds-the-Fire's name can also be interpreted to add to his importance as a character. As a baby, Thomas was rescued from a burning house by Victor's father. The event with the fire inevitably led Victor's father to leave, and Victor blames or is at least reminded of, his father's absence by Thomas. The fire is a point of blame for Thomas, yet Thomas's name incorporates that fault. Alexie does this to show the importance of using your short-comings to define oneself. Using your short-comings as defining factors makes a person humble and conscious of mistakes and therefore wiser.
This is more evident after Thomas and Victor go to Arizona to reunite with Victor's father. The trip to Arizona teaches Victor a lot about who he is and what his values are in connection with the absence of his father. Thomas uses his oration and openness to comfort Victor, and Thomas becomes a source of friendship for Victor. One lesson he teaches Victor is that you should always be proud of who you are and never be afraid to tell your story, and Thomas-Builds-the-Fire's name exemplifies those qualities.