How do you cheat on the ACT? I remember it and it would literally be impossible.
There could be impropriety at the testing facility but that's not usually the case. It's usually the case that the system flags a result based on either a lower previous test or GPA that would not align with the score. It's usually a matter of validating grades and such.
I dont have any inside information to this case specific, but often times it's actually the incoming school that is blocking things just to make sure there wouldn't be any trouble giving financial aid to a student with a flagged result. The NCAA can sometimes be slow in letting everyone know things are alright.
Going by public knowledge I would predict he eventually gets cleared, just a question of when.