I've not seen that discussed either. Very few can do that in 3 years so i doubt it's the case. M. Gessell did but it's a rare occurrence. Granted, they go to summer classes, but still.
My guess is that if he was on track to graduate in 3 years it would have come up by now.
Sorry, I was not clear. If he can graduate in 4 years, that should be important in him deciding to stay after 3 years.