Drew Brees may have come out of Purdue, but he's about as relevant here as Otto Graham is given that no one who coached him is here now.
Mick McCall has done a good job of spitting out QBs who have done well, including Omar Jacobs (HM and 2nd team All-American in 2004 and 2005, Davey O'Brien Semi-finalist, Drafted by Steelers), Josh Harris (drafted by Ravens), Mike Kafka (drafted by Eagles), Trevor Siemian (drafted by Broncos, started more games than any QB tutored by Brohm), and Clayton Thorson (going to be drafted at the end of this year). I'm not sure Brohm has anything on McCall in terms of developing QBs, quite frankly.