which character changes from the beginning to the end of the story? explain

Of all the characters in the story, it is the father who most changes from the beginning to the end of the story. When we first meet him, the father has a great job and travels extensively. It is only through his letters that we get to know him as a person, as he's separated from his family and faces an interment that not only imprisons him but isolates him from those he loves as well. When he is finally reunited with his family, he is described as a far different men than the father they remember;

"The man who came back on the train looked much older than his fifty-six years. He wore bright white dentures and he'd lost his hair. Whenever we put our arms around him we could feel his ribs through the cloth of his shirt. He did not draw for us, or sing songs for us in his wobbly off key voice. He did not read us stories."