I don't think he's made up his mind. A lot of people point to his avoidance of questions and that he hasn't signed an extension. Here's the deal broken down as I see it:
1) He didn't expect to be this successful, this fast. He's said this repeatedly
2) He did not expect Riley to get fired at Nebraska this quickly.
3) This opens up a vacancy at his alma mater that he wasn't planning on. The lure is strong
4) Because he loves BOTH school intensely, he thinks the RIGHT and HONEST thing to do is to listen to both pitches, both deals and weigh them in the context of everything else.
5)It's not just about money either. He has to factor in the coaches he has vs the coaches he would want at NE, and rolled into that is what kind of leeway he gets to make those decisions up there, PLUS the willingness for current coaches to leave. Some may want to, others love it here and may not be so quick to jump ship.
This is all in the context of him making great friends, relationships here (players too). People mentioned the recruits he brought here. That gets factored in. His baby was just born here during this remarkable season. He may think "what else can I do here?" but he may also think "We are just getting started"
I truly don't think he knows. I think he's doing is best to focus on the task at hand. He'll listen to Nebraska, probably Sunday. He's a religious guy too. Even though I'm not, he'll probably "pray on it" and go with what feels right to him. He doesn't like to make hasty, emotional decisions. He may very well think he's ready for the "big time" at Nebraska. But he may honestly feel that he needs a few more years to get his coaching chops up to snuff. Who knows. Frost probably doesn't even know yet.
But these done deal reports and all his crap is so ridiculous. Will it hurt the program if he leaves? you bet. But if he leaves, we should all thank the ever loving hell out of him for giving us this season. Is it enough? No. It's never enough. Personally I think our fanbase will give him so many chances to make mistakes and prove himself. I don't think he has that kind of leeway at a school like Nebraska, ESPECIALLY coming from an undefeated season like we have here. They are going to expect immediate results, and when they don't get them, they'll curse his name like they did 20 years ago.