Continue to show full time.
The half time or more on the 1098-T is all that's necessary to qualify for the tuition credit. He still needs to be full time to qualify as a "Qualifying Child" dependent.
There are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, student status, a relationship test and residence test. Only a QC qualifies a taxpayer for the Earned Income Credit and the Child Tax Credit. They are interrelated but the rules are different for each.
