Where is trust a theme in the story "The Red Convertible" by Louise Erdrich?

In the story, the trust between two brothers is an important theme. It is alluded to when Henry goes to fight in the Vietnam War and leaves his trusted red Oldsmobile in Lyman's care.
When Henry was alive, both brothers often took road trips together in the Oldsmobile. They were happy to travel, and enjoyed great adventures together. After Henry became a Marine, he stayed away for three years fighting in the war. Before he left, he gave Lyman his keys to the Oldsmobile. His actions demonstrated his great trust in his brother. He told Lyman to treat the car as his own. While he was gone, Lyman took good care of the car; he kept it in pristine condition for Henry's return.
After Henry returned from the war, however, he was a different man. He became a loner, and he was always mean and easily irritated. Lyman reports that it was difficult to get Henry to laugh, and when he did laugh, it often sounded more like a man who was choking. Although Lyman had kept his brother's trust in him (where the Oldsmobile was concerned), he soon felt that drastic measures were needed to shake Henry out of his self-destructive stupor.
Despite his reservations, Lyman took a hammer to the car. He made the car look so beat up that Henry eventually noticed. Lyman then challenged Henry to restore the car to its initial condition. This conversation was the catalyst that precipitated Henry's frenzied work on the car. After the car was restored, Henry invited Lyman to take a ride with him. At this point, Lyman began to let himself hope that his brother was back to his old self again. The story ends in tragedy, however, when Lyman is swept out to deeper waters by the river currents, in which he drowns.
The trust between the two brothers is one of the main themes in the story. That trust is alluded to when Henry hands his car keys to Lyman just before he leaves for the war. It is again highlighted when Henry quietly repairs the Oldsmobile for Lyman, even though he knows that Lyman damaged the car on purpose. Henry's continued trust in his brother is poignantly and clearly demonstrated when he insists that Lyman take the car for his own. Perhaps, knowing that his life will never approach any sort of normalcy again, Henry gifts the car to Lyman as an emblem of his trust and love.