As you surmised, he cannot be your dependent, if he provided more than half his own support. If he cannot be claimed as a dependent, he may claim the $1400 Recovery Rebate credit (Stimulus). You have to do the support calculation. For that calculation, scholarships and what they pay are ignored.
The support value of the home, provided by the parent, is the fair market rental value of the home plus utilities & other expenses divided by the number of occupants.
The IRS has a worksheet that can be used to help with the support calculation. See: http://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf
He can claim the refundable portion of the American opportunity Credit (AOC), if more than half his support came from his own earned income. Note that for the dependent test, his self support does not have to be from earned income.