In the short story "Soldier's Home" by Ernest Hemingway, how would you characterize Krebs?
Krebs has Post Traumatic Stress Disorder*. He has gone from a typical American young man to a completely disillusioned one. He goes through phases of not wanting to discuss the war, then when he wants to, no one wants to hear about it. He understands being a Marine--following orders made him "feel cool and clear inside"--but he doesn't understand where he fits now that he's back home. He is a changed man, and no one close to him can possibly understand what he's struggling with. He's trying to have a normal life, living with his family, keeping a routine of sorts. He looks at the girls in his home town, but while he'd like to have a girlfriend, he doesn't want to have to work to get her; he is afraid he'll have to tell more lies and he's just too tired and doesn't want any consequences. In this way, he is methodically separating himself psychologically from his own life.
He has been immobile and not dated for so long that his parents are clearly worried. They give him access to the car and hint that he should go on dates. His mother asks if he's thought about what he's going to do, because "it's about time," and he doesn't know. He can't tell her he loves her and he can't pray. He is completely withdrawn, and feels he has no one to talk to.
* Some classic PTSD symptoms that he exemplifies are as follows: negative feelings about yourself or other people; inability to experience positive emotions; feeling emotionally numb; lack of interest in activities you once enjoyed; hopelessness about the future; and difficulty maintaining close relationships.