What are the motifs in The Red Convertible by Louise Erdrich?

Wartime trauma is a recurring idea. Initially, Henry is seen as an easygoing, funny, carefree young man. After spending three years fighting in Vietnam, however, he was a very different person. Describing Henry after the war, Lyman remarks:

When he came home ... Henry was very different, and I'll say this: the change was no good. You could hardly expect him to change for the better, I know. But he was quiet, so quiet, and never comfortable sitting still anywhere but always up and moving around.... He'd always had a joke ... and now you couldn't get him to laugh, or when he did it was more the sound of a man choking, a sound that stopped up the throats of other people around him. They got to leaving him alone most of the time, and I didn't blame them. It was a fact: Henry was jumpy and mean.