MB, I suggest Google Earth (http://www.google.com/earth/). Once in the program have your son pinpoint his location. In the bottom right of the page he will find the lat/long and height above sea level. Use this reading to compare against interesting places (ie nearest downtown, known cel tower etc) and it will give him a rough idea of how much antenna (and type) he needs. If his location is higher than anything for about 50 miles then selection is unlimited. However, if he is in a hole (lower than anything around him) he will need to get an antenna on some type of mast and get it up in the air.
A simple antenna to build is a J-Pole (http://www.buxcomm.com/jpoles4ever.htm). I have made many to include one that folds for storage.
Lowe’s has top rail post for chain link fencing that can be used to mount antenna and get it up in the air. One end is tapered to fit inside the end of another post. (http://www.lowes.com/pd_103268-215-58910235___). Drill holes at the top and at the middle and attach guy wires. If you need to go higher than 35ft then I recommend a tower. I get tower sections by keeping my eye open for ones laying on the ground next to buildings. Just ask the owner if they plan to use the tower section. Many times I have people ask me to “please” take it!