What do the characters' emotions and behavior reveal about their psychological states in "Soldier's Home"?

Ernest Hemingway's short story "Soldier's Home" is about a returning World War I veteran who fought in some of the most important battles of the war. There are essentially only four characters represented in the story: Harold Krebs, his mother, father and sister. Krebs apparently is suffering ill effects from his experience in the war. He lacks motivation and claims that he wishes to avoid complications and for everything in his life to "go smoothly." His days are spent basically in an idle state, sleeping late, spending time at the library (trying to sort through books on the war to figure out what really happened to him) and shooting pool. He is unable to communicate his unease about what he went through in the war and tends to avoid interpersonal relationships. In today's terms it might be said that Krebs suffers from post-traumatic stress disorder. His psychological state is one of a man who has experienced the horrors of war and is not capable of returning to his old life and normal existence. Two recent movies, The Hurt Locker and American Sniper, portray characters who would relate to what Krebs is feeling as he attempts to reintegrate into life in his small Oklahoma town.
Krebs's mother is also affected by her son's unease. She cannot understand why he won't simply carry on with his life as if the war never happened. She finally confronts him at the end of the story in an extremely uncomfortable scene in which Harold tells her that he doesn't love her and cannot pray with her. James R. Mellow, in his biography of Hemingway, suggests that Mrs. Krebs is modeled after Hemingway's own mother and that, along with being devoutly religious, was also a highly controlling figure in her children's lives. The fact that Krebs is no longer her little boy has caused her great dismay and she eventually breaks down crying in the face of his rejections.
Krebs's father is never physically present in the story, but his presence is felt. He is obviously a no-nonsense businessman who simply wants his son to get on with acquiring a job and being a productive member of society. His absence suggests that he may not be emotionally invested in his son's life and that the only thing that really matters to him is work.
Finally, the reader is introduced to Krebs's sister Helen, who appears in a seemingly unimportant scene in which she asks him if he is her "beau" and wants him to attend her indoor baseball game. She tells him that he doesn't love her unless he goes to her game. Krebs is initially apathetic and noncommittal in his conversation with his sister, but the discussion is later revealed to be important. In the story's last lines he says he will go to Helen's game, and this may be the first realization for Harold that he must get on with his life and that he may actually be capable of loving someone.