Under the circumstances, this is the best decision for Greico. He is very young and needs to be playing regularly. In hindsight, he probably should have waited another year before moving to UND.
As for the OHL, he can still get an education once he's done, if things don't work out hockey wise. I wouldn't be surprised if he got a pretty sweet deal to move over. It's not unheard of for these guys to get 100K to sign.