What is the significance of the way Sam and Emmett deal with Vietnam?

Emmett cannot cope with the PTSD he suffered as a result of the war. In essence, he completely shuts down, unless of course, he is with other vets..... other men who had similar experiences.

Sam, who lives with her Uncle Emmett is trying to understand both her father (who died in Vietnam), and her uncle. When her grandmother gives her a copy of her father's diary, she is shocked by much of what she reads.... appalled. Thus, she makes it her own personal goal to understand the man who wrote those diaries, as well as her Uncle.