Let's be honest, his plan was to be here only 1 year. I'm sure he's doing the bare minimum when it comes to academics. Someone like that might not even be passing classes right now because plan A was to leave.
Deciding between the NBA life/money and having to come back and take more classes has to play into their thought processes. If I were in the same spot, choosing to not have to deal with classes anymore sure would be tempting.