Agree, time to move on. Our daughter was miss independent, very mature, was away from home in high school and went off to college to a private Christian college in Arkansas. She couldn't wait for us to unload her things and get acquainted with her new roommate and surroundings. In a couple of weeks that all changed and it was a struggle to get her to stay in school. Even the school was worried about her and kept a very close watch on her. It happens and you can't predict it. It is also easier to put the reason (use blame here if you want) on someone or something else as "the reason." In the end it doesn't matter.
I don't know how many athletes start the fall at Nebraska - how many football alone? 150? I know 105 can report early. So this is a relatively small occurrence. It is too easy to bash the kid and focus on the excuses, but to him it is all real. I just ignore and go one. It happens, so what. The more we keep it alive the worse it gets. My guess is the greater student body has a higher percentage of this than the athletes as the athletes have a built in support group. That is just a guess.
I hope he does well at the JC level, best of luck to the kid and mostly I just hope he is happy with his decision.