Q. Does income not play a role under these circumstances then?
A. No. Income is irrelevant for the "Qualifying Child' rules. It doesn't matter how much he earned. What matters is how much he spent on support.
On the other hand, if a child/student does not meet the QC rules, income is a factor in whether he can be claimed under the "qualifying relative" (standard) dependent rules. There is a $4300 income limit.
But, since you are a fulltime student, under 24 and live at home, you come under the QC rules, not the qualifying relative rules.
