Did he announce? I missed that. If he didn't announce why did he have a final four instead of just saying "I am going to Maryland". I am confused.
He is still considering ISU but due to the visit restrictions being extended he won't be able to make it to campus to visit. That could be the deal breaker for him and his family. Where he has a long standing relationship with Turgeon and had on official to Maryland previously ( visited Seton Hall too).
I'd say Maryland and SH would be considered the favorites today due to familiarity but obviously Prohm has made a serious impression to be in the final four in a short time to be a real threat to get his commitment. I'd speculate Michigan is more of a result of Juan Howard being the coach being the draw than anything else.