Symbolism, Imagery, Allegory
The young man represents all of the faceless Vietnamese dead. There were hundreds of thousands of Vietnamese dead, and many went unidentified, burned by napalm or buried by the American soldiers:
There were many bodies, real bodies with real faces, but I was young then and I was afraid to look. And now, twenty years later, I'm left with faceless responsibility and faceless grief. (Good Form.7)
With the young man on the trail, O'Brien is trying to give the Vietnamese victims some dignity and an identity.