你儿子必须在学校州报税才能将州税拿回来。As long as he is still a full time student, and under 24, makes less than the personal examption $3700, and you are supporting him more than half of the year, you can still claim him as dependent. He can file his own tax return to get refund.
Disclaimer:我不是会计师，check IRS website for more accurate information.
