What are we told happens to Norman Bowker? How do we know this?

We are told that Norman returns home after the war, and that he has a difficult time adjusting to life at home. We also learn that he can't talk to anyone or share his experiences.... not even with his father. He's had a few different jobs, but he's never been able to settle on anything. We learn what happens to him because of the letter he sends to O'Brien.