12 or 13 credit hours is full time. But in order to graduate in 4 years you have to average 15 I believe. I think at Iowa the requirement is 120 credit hours to graduate with the last 60 being earned at Iowa.
But in all honesty there are far to many variables to figure out where he is in his college career for a degree.
I do not recall, did Tyler sit out a year after transferring from Iowa?
If so, then he is most likely behind. He would basically be looking at 6 years to graduate. Then again, depending on the classes he took at Iowa, I would assume they all transferred, but were they the right classes to count toward his degree. Did he possibly change majors?
If not and he is in his fourth year he could easily be that far short. 12 hours this spring and then 2 semesters of 12 hours next year would have him graduate in 5 years. Not all that different from plenty of students that take 5 years today.