Did he get a 1098-T form for 2018? Was the 'At least half-time' box checked? If so - you're Definitely good to go, as that's the only indicator IRS has of full-time status.
Yes, he did get a 1098-T. The IRS doesn't consider him full-time for 2018 and therefore I can't claim him as a dependent for 2018 because, he made more that $4150 and wasn't a full-time student during 5 calendar months in 2018. Sigh, so now I don't think I can get the American Opportunity Tax Credit.
If he had more than one school he attended, And the combination rendered him FTS for the five required months - Then he was a FTS for the year ...
Yes. Generally speaking, you are considered as a full-time student if you enroll in school for at least five months in the tax year.
However, each school defines "full time" in its own way (usually in terms of the number of courses or hours). Is September the normal semester begin date for your school?
If so, then you can consider yourself full-time if your course load is classified as full-time by your school, and answer 'yes' to the full-time question.