If Walters does not have enough respect for Purdue to resign, which he probably will not do, this is what Purdue needs to do!
Demote the current DC to another position, demote Walters to handle the defense, so we can see for ourselves if he really is the defensive genius he was touted to be! No use paying
these coaches to sit home and draw paychecks, let them do some work to earn what they are owed!
Start an immediate search for a new head coach. Do not allow the AD to be in charge of the search, because he has proven he is not qualified to do that job! Instead hire an experienced search firm to find the candidates Furthermore there's plenty of time available to find a new coach so the search can be a thorough one!
Let the quarterback start calling his own plays!
Appoint an assistant AD as interim head coach - hopefully one with football experience!
None of this would be detrimental to the program, since the program has already reached bottom!