He is located between Primm and the NCRCF compound only if Eddie is betrayed during I Fought the Law. Otherwise he will be encountered when the NCR raid the prison while the Courier is inside backing up the gangers. If the NCR are assisted in retaking the prison he will permanently take up residence in the prison's administration building.
"I'm Sergeant Lee. Lieutenant Hayes radioed ahead to say you were on the way. We've got surprise on our side, and that's about it. Once we blow a gap in the fence, we've got to pour on the fire and keep them disorganized."