Q. How is his "support" calculated?
A. 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
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.
Scholarships are excluded from the support calculation.
Q. The scholarship pays for room and board and both parents do not work, so they don't file taxes. So is he a dependent on himself?
A. No. Based on your brief description, he does not provide more than half his own support. But the only way to sure is to run the support calculation. Note that scholarships are not support provided by him.
Also note the dependent test is about overall support. The AOC question is about support from his earned income.
