I mean - why WOULDNT he sign on. Show up late in the season - chance to earn a ring. Dream situation for many guys.
As far as future in coaching - not to take anything away from him - but Northwestern program is a traditional powerhouse nationally. One down year and he steps in and wins - but how much money did the boosters pay out ? I’m guessing more than a few parents suddenly decided their star athlete child would get an education at this powerhouse program school.