This is just my thoughts but what more does Trev need to see?
NU is in the weakest division in P5 football. Wisconsin is horrible and only getting worse. Minny had their year and since then have been back to ,500 ball and they will be worse next year. NW is bad. Purdue is bad. Illinois is horrible. Iowa is "the class" of the division this year and they are only favored by 4 at MD this weekend, think about that.
This division is ready for NU to do anything at all.
A competent coach wins this division 75% of the time.
I don't even know if winning 4 more matters. NU should not be struggling to make a bowl game.