I agree with those who are being cautious with their optimism.
My biggest question is, why didn't he just enroll in the fall and play a full year at UConn? What has changed that makes him willing and/or able to come now but not then?
Second, it takes time for any kid to adjust to the speed of the college game and it takes time to gel with your teammates. Coming in mid-season without even practicing with the team before is not the best way to get a strong start or even to be ready to be a major contributor come March.
Third, I would be concerned about team chemistry. Hell, I worry a little about team chemistry with a one-and-done, never mind a 0.5 and done! Even a one and done has to come in and replace a player that wasn't already a major contributor and you don't expect to become a major contributor. Drummond is a great kid by all accounts and very gifted but he struggled to contribute and caused team chemistry issues. They weren't at all his fault but they happened.