As others have said, as long as he did not provide more than half his own support, he can still be your Qualifying Child (QC) dependent for the EITC. You will only get the Other dependent Credit ($500) instead of the child tax credit, since he is over 16. But, he is still a QC for purposes of the EITC. Scholarships, including the $6600 taxable part, are not considered support provided by him, for the support test.
He does need to file a tax return and will owe about $800 of federal tax. The scholarship income is considered unearned income and the "kiddie tax" will apply (a portion of the income will be taxed at the parent's marginal tax rate.
