I would sit down with him and lay out what's what. List all the things that need to be done and by when and have him figure out how to deal with the consequences. If he doesn't get the scholarship stuff in place, then he has to find a way to make $2500, IMO.
If there's a reason he doesn't want to go to school (my SD is dragging her feet), try to find out why. My SD is worried about leaving everything she knows, which is understandable. If he doesn't go to college now, what is his plan? Surely video games and pizza and your basement won't fly.
My SS wants to come home for a year between undergrad and grad and was stunned when DH told him he'd pay rent. I bet that the rent still won't cover the HUGE increase in food and utilities that he brings, but it will offset the expenses. If SS doesn't like our offer, he can live with his mom or somewhere else.
SS has mostly gotten his act together, went abroad for a semester, did live on campus, and is graduating with a good GPA and a direction even if he's still living on the last minute. He's a HUGE procrastinator and spend most of his family time this break either working into the wee hours on papers that were overdue or shopping for Christmas. Sigh.
I was surprised at the amount of support frosh at SS's college received. I was basically thrown to the wolves. I had a curfew for guests in my freshman dorm, but there was no one caring about my grades but me. See what his chosen college offers. It may alleviate his fears.
You might also find out he doesn't want to go away yet. My cousin is doing 2 years at community college and then considering if he wants to save room and board and transfer locally or not. There are many roads to Rome.