there are different rules if he's your qualifying child. the issue of whether he's a qualifying child or a qualifying relative probably depends on his student status since he's over 19
you can claim him as a qualifying child if all these tests are met
• he has the same principal abode as you for more than ½ the tax year. Temporary absences like for school are ignored
• if he is not a full-time student, he's under 19 at the end of the tax year. If a full-time student, he's under 24 at the end of the tax year.
• he hasn't provided over ½ his own support
• he didn't file a joint return unless there was no tax liability but merely filing jointly to facilitate a refund of taxes withheld or estimates paid
a full-time student is one who is enrolled full-time in school (but not online or correspondence schools) during any part of 5 calendar months during the calendar year
he would still file his own return to report his income. if he is a dependent you can claim, he must so indicate on his tax return even if you do not in fact claim him on your return.
