If he's not using Google Maps, but rather, GOOGLE EARTH, he may be having problems because of the terrain. When terrain is added to the view, I find that the longitude and latitude have accuracy problems (especially with the Google Earth Geocaching component). If I change views, the geocaches will jump around on the map. They show up in different places with every view. Tell him to turn off the "terain" layer, and that may help him get a more consistent view.