how does Fredrick Henry's perspective of the war change ?

The protagonist and fairly aloof narrator, Henry is a young American ambulance driver with the Italian army. However, he does not feel strongly about the cause, and certainly is not out for glory. He turns from the horrors of war to a passionate, escapist love affair with Catherine Barkley, and the all-consuming love helps distract him from the brutality around him. Still, he is good at his job; a cool-headed, unselfish man who exercises grace under pressure when he is injured and when he must shoot a deserting engineering officer, Henry fulfills the code of the "Hemingway hero." He makes his "separate peace" when he decides that he no longer has any obligation to the army and that his loyalty is to Catherine.