In order to claim a tuition credit or deduction, the student must be your dependent. If he does not qualify as your dependent, he may count the $2000 you paid toward claiming the credit on his return*. If he is some other person's dependent (e.g. other parent) that person may claim your $2000 to get the credit for himself. It's one of the very few times you can count other people's money to claim a tax credit.
* A full time unmarried student, under age 24, is only eligible for the refundable portion of the American Opportunity Credit, on his own return, if he supports himself by working (earned income).
