If you are claiming your son as a dependent on your tax return then any education expenses are entered on your tax return.
Q. Do I get a tax break for paying college tuition for my son?
A. Only if you are claiming him as a dependent.
But, whomever does claim him, whether it be the other parent or the student himself, they may count the tuition and expenses, you paid, in claiming the credit for themselves. Although the general rule, in taxes, is that you must be the one making the payment, to get the deduction or credit, there is an exception for education.
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Q. Should the student be claiming the education credit, on his own return?
A. Probably not.
While technically there is a provision that allows your student-dependent to claim a federal tuition credit, from a practical matter it seldom works out. A full time student, under age 24, is only eligible for the refundable portion of the American Opportunity Credit (AOTC) if he/she supports himself by working. She cannot be supporting herself on student loans & grants and 529 plans and parental support. It is usually best if the parent claims that credit.
If the student actually has a tax liability, there is a provision to allow him to claim a non-refundable tuition credit. But then the parent must forgo claiming the student as a dependent, and the $500 other dependent credit. The student must still indicate that he can be claimed as a dependent, on his return. This is worth up to $2500 (AOTC shifts to all non refundable)