He is wrong. A transformation is a reduction when the scale factor is between -1 and 1. If the scale factor is greater than 1, then it's a dilation.
In this case, the scale factor is a fraction, but fractions can represent numbers outsise the [-1,1] interval.
In this case, in fact, 8/3 is an improper fraction, meaning exactly that it represents a number greater than 1.
So, this transformation is a dilation, becase the scale factor 8/3 is greater than 1.