That's weird... Here's a quote from the Idaho DMV:
Lawful Presence -- You will also be required to provide proof of lawful presence if you are not a citizen or national of the United States. Acceptable lawful presence documents include:
Certified original U.S. Birth Certificate
Certification of Birth Abroad
Original Certificate of Naturalization/Citizenship
Permanent Resident card or Resident Alien card
Employment Authorization card
Valid Foreign passport with valid U.S. VISA and I-94 (Arrival/Departure record)
http://www.itd.idaho.gov/dmv/DriverS...ense_facts.htm
If your friend bought a fake ID, he will be caught and reported.