I haven't seen any discussion on that specific issue.
Then there's the other issues; with only $5-6K of income, he's unlikely to be able to use the non-refundable portion of the AOTC. And there are restrictions on students claiming the refundable portion.
Most students simply aren't eligible. A full time unmarried student, under age 24, even if you don't qualify as a dependent, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working. You cannot be supporting yourself on parental support, 529 plans or student loans & grants. You usually must have actually paid tuition, not had it paid by scholarships & grants.
Reference: Line 7 instructions for form 8863. https://www.irs.gov/instructions/i8863
