Is he really a late bloomer? He's about the size of the average US male and he's a HS sophomore. Unless he's going to be 6'2 - he's on the normal path of a high schooler. How much bigger are the other sophomores that you feel he's behind physically?
How is his summer team? How do they place their guys? What do the last 2-3 senior classes for his club look like college wise? Is he going to be playing varsity this year?