"Any game action that disproves this Mich player's statement?"
The closest offering I can think of us that, Mich has scored their 3rd TD near the end of the 1st Qtr, then 4 minutes later, they are stopped and kick their first (of two) FGs. Can FGs be considered a 'stop' by the Defense?
I think that, early on, that first FG was considered a 'good stop' but I don't recall each of Mich's failed plays just before that FG. I think one was an errant pass - badly thrown. Not really a defensive gem, therefore, but a poor offensive one. I don't recall the other two. There were stops during the game, and some of those were indeed good-enough defensive plays which indicate a non-quit attitude.
I suspect this one player's quip was his own anecdotal selective memory although, in fact, beating a Quitter Team by ONLY 56-10 really doesn't speak too highly of Mich. A really good team would have put up 100 or more, right? I mean - since the other team 'quit'. Right?
With any luck, this can be Bulletin Board Material... and the team really has few choices of how to use this item into their future. Fortunately, Frost has a long history of resurrecting failed, quitter programs, right? He knows all about this, right? (This will always be my complaint against Frost: he does NOT have a long history of coaching in a variety of situations. He's still a very young coach in practice. This will be tooth-cutting situations for the next decade for him.)