He is under the game world similar to the missing NPC's in Fallout 3. I found a way to reach him by glitching out of "Aerotech Office Park" and going to the marker. This allowed me to complete the quest. I would post a Youtube video, but I dont have the resources for that. If someone could try this and post a video for everyone and also put it on the wiki that would be great.
Below is the location where I glitched out(SW corner of aerotech), im hoping this doesn't get patched. You need to get on top of the building and jump down outside of areotech.
http://imageshack.us/photo/my-images/809/800pxaerotechofficepark.jpg/