Dawes claims he was originally the leader of a gang in the Hub back in California. However, he was apprehended and sentenced to imprisonment in the correctional facility in the Mojave Wasteland for starting a riot. Assuming that the player hasn't already made enemies of the Powder Ganger faction, Dawes will grant access to the NCR Correctional Facility in exchange for 100 caps. Alternatively, if the player has assisted Joe Cobb in Run Goodsprings Run, he will let the player in for free.
If the player is wearing faction armor to improve their reputation with the Powder Gangers, Dawes will note that he doesn't recognize the player as somebody with whom he served time and will still demand the entrance fee of 100 caps. However, after paying and the player moves closer Dawes will see through the faction disguise and attack the player. Killing Dawes at this point will not make the others hostile unless killing him also causes your reputation to drop to vilified.
With no more than a modest Sneak skill, it is possible to achieve Hidden status beside or behind Dawes and pickpocket his NCRCF visitor's center key (a much easier skill check than for any of Dawes' other possessions). There is no Karma loss for successfully pickpocketing the key, nor for using the key on the door, so this is a non-confrontational way to bypass the 100 cap bribe.
He'll greet a female player more nicely than a male player.