That is correct, student employees of colleges are exempt from FICA, but not income tax. So, he just enters it like an ordinary W-2. TurboTax will not be confused because boxes 3,4,5 & 6 are blank. The fact that box 2 is blank or 0 is probably because his income is low and no income tax was expected (or just because of how he filled out his w-4.
