It's nearly impossible to know what he knew, but we do know this
Boeheim has a history of low graduation rates
Boeheim has a history of acting arrogant towards his critics
Boeheim has a history of allowing troubled players to play (Hawkins, Mello)
Joe had a history of graduating his players
Joe stood by some of his kids when they got in trouble (Casey) but was quick to get rid of others (Scott)
It's a lot more difficult to manage 85+ kids than 12+ kids