If the company will ship to a PO Box just use his regular mailing address.
If company won't ship to PO Box and has to have street address, use the pak mail address:
Cadet John Doe
2302 Cadet Drive, Box XXXX (his PO Box number, but don't include the 'PO' part)
USAF Academy CO 80840
Note the different zip code. Pak mail needs the Box # to separate the packages.
There is a $3 (might be $2) your cadet will need to pay at pak mail to pick up the package.
They don't get notification they have a box at pak mail, and pak mail is not in the same building where they get their regular mail. (might be Harmon Hall, but don't know for sure -- he could definitely ask his C3C 'coach' where pak mail is)
Other possibility is to ship to his sponsor's house (get their approval first to mail stuff there) and avoid the $3 fee to pick up the package.