I know he can typically retake a class and replace the grade, but I don't know how that all works when retaking a class from a different school from the one you originally got the grade from. It may be that he is stuck with the GT grades unless he retakes them through GT, which he isn't doing. Also, I know he was kick off the team for the failed drug test, but did he finish out the semester? If he didn't then he may have some failing grades to make up for. Either way it sounds like he has learned some lessons and has been trying to get his life in order. I hope he is able to work through the consequences of his past issues and make it to NU.
While I think that the Nebraska kid thing gets way overplayed here on this board, I do think that if he had to, Mazour could be a quality player at the RB position if we needed him to step into a major contributing role. I don't think it will come to that but won't be worried if it does.