Money paid directly to your student son is not a qualified education expense. Only money paid to the school from any source (your, your son, scholarships, 529 distributions, etc) are qualified education expenses. The only qualified education expenses are books, tuition and lab fees. That's it, with no exceptions.
If 529 distributions are involved here, then in addition to the qualified education expenses mentioned above. 529 distributions can also be used for the unqualified but allowed expense of room and board, provide that room and board paid was "in direct support" of the education.
So if the student did not enroll as a full time student for the summer semester, room and board expenses paid for those months are not an allowed deduction.
