An NCR grunt caught in Camp Searchlight when Caesar's Legion released a load of nuclear material that irradiated the whole town, Private Edwards is now a forlorn ghoul hiding out in one of the accessible houses of the town.
When asked why he hasn't left yet, he tells the Courier that he's too afraid of the outside radiation causing him to go feral, radscorpions and of a less-than-warm welcome by fellow NCR soldiers. This is not unfounded, as First Sergeant Astor believes that it is better to shoot NCR soldiers that turned into ghouls in Camp Searchlight, to end their suffering.
Private Edwards still says the general dialog a normal NCR Trooper would in New Vegas and throughout the Mojave Wasteland.
Although Private Edwards claims that he can't serve the NCR because he's ghoulified, there are NCR Veteran Rangers that are ghouls as well. This can be seen at both Ranger Station Echo and Camp Golf.
A speech check of 60 will allow you to lie to Private Edwards making him believe that the radscorpions have all gone. Once you leave the house you will find his dead corpse and be ambushed upon by three giant radscorpions. You gain 60 XP and lose Karma for this action.
Speaking to First Sergeant Astor about Private Edwards reveals that he thinks he should be killed to end his suffering, despite knowing he isn't feral. When pressed he suggests he might head to Ranger station Echo as they are run by a ghoul. A speech check of 50 or intelligence check of 7 will persuade Sergeant Astor to let Edwards rejoin them, who will reward you with 50 bottle caps and karma if you give him the good news.
You can tell Private Edwards that First Sergeant Astor believes he should be killed, and a speech check of 50 will persuade him to kill Astor first. He will immediately leave the house and head towards the NCR group nearby, picking up a small group of Feral trooper ghouls along the way and begin a small battle. Private Edwards and the ghouls will be easily killed by the four troopers without assistance.
If you send him away before you get the Irr. Dog tags, he'll drop the dog tags in his house.
If you convince Edwards to join Ranger station Echo and then kill him, you will gain NCR infamy.
If you kill Private Edwards in the living room of the Camp Searchlight home you find him in, and then steal the harmonica on the shelves behind the couch, you may hear his voice telling you that "You can't just take that", despite him being dead.
You can also just send him into the Mojave Wasteland to do some exploring on his own.