The vagrant is an old, and apparently homeless, man who lives in Freeside. This non-player character seems to be pretty much useless, like the destitute traveler. Other than that not much is known about him.
I Could Make You Care: When the Courier needs to ask around Freeside about a rangefinder, dialogue with him is possible. The Courier can pay him for the information, threaten him (Strength 7 needed) or if they have low Intelligence there is special dialogue line which makes him talk like an intellectual person (similar to Torr from Fallout 2).
PC Sometimes, if the player kills the vagrant, you will hear quotes like "Are you crazy man, I've got two kids to feed!" or, "Help!", similar to when your reputation in Freeside is lower than neutral, and Freeside thugs try to mug you but flee. [verified]