I think the key for Thorne is to keep the two issues separate. The first is whether he qualifies for a medical redshirt; i.e., had this happened in his second, third or fourth year, would he qualify for a medical hardship waiver. It appears that Hayes got a waiver for his first year three years after the fact, in spite of the fact that he played in the second half of the season in question. Hayes' injury took place before that season. One could surmise that he tried to play several times in both the first and second halves of the season but was unable to do so. Big Mike tried only once in the second half of the season. The key point seems to be that playing in the second half of the season is not automatically dispositive. Instead, the question is whether the season ending injury took place in the first half of the season.
If and only if he qualifies for a medical redshirt do we reach the question of whether he can get a waiver for a sixth season. I think his chances are much better on the second question than on the first. We already know he got a medical redshirt as a freshman. That would mean he missed two seasons for reasons beyond the control both of him and of his team(s). Reasons beyond control for BOTH missed seasons seems to be the essential element of getting a sixth season. It is hard to think of anything better than a medical redshirt to qualify on the "beyond control" of player, coach, or administration issue.
I just hope that those who say the NCAA usually acts quickly on this sort of issue (unlike seemingly all the other issues that they manage to put off forever) are right. If so, we should know the answer in no more than two weeks.