In The Things They Carried, I would choose "The Man I Killed," "Sweetheart of the Song Tra Bong," and "The Lives of the Dead." All of these stories are connected to Tim's view of death and how he is actually writing to women, his ideal readers, as part of a coping process. He knows that if he can get a woman (his daughter, Linda, Lemon's sister, the "dumb cooze," or Martha) to understand war and death, then he has succeeded as a man, a soldier, and storyteller.
Most of the men, after they have killed, internalize their feelings, whether it be guilt, anger, depression, or loneliness. Bowker's the best example: no one in his hometown listens to him, not his dad, not his ex-girlfried. And so he kills himself because of a lack of communication. For O'Brien, the best way to deal with death is to talk about it and, better yet, write about it. Not only should one write about it, but he should write to someone who might even hate him for ever being a solider and killing in the first place: a woman (like Martha or Kathleen or Lemon's sister).
You have to decide why O'Brien does this: why are women his ideal audience for dealing with death? Are women better listeners? Does the wife, mother, and daughter comfort and forgive better than the male equivalents? Are women able to give soldiers who've experienced death a better sense of purpose? Is the female community at home, ironically, stronger than the male one that goes to war?
When a soldier dies, all the soldiers in the company loose something. After O'Brien killed "the man I killed" he seems to have taken on the guilty feelings that Cross took on with Lavender's death. The part of O'Brien that was killed with him, whether it be innocence or inexperience, was not replaced with something, like courage or guilt. O'Brien's point is that war first leads to a death of one's identity, and the lack of identity that follows is a vacuum that may be filled with guilt (Cross), fear (Lavender), an overdependence on camaraderie (Kiley), a rebellious spirit (Bell), or nothing at all (Azar).