Have to think Brohm's agent is talking to Purdue's AD, at the very least to increase his client's bargaining position with UT.
(1) I assume Brohm's ultimate goal is to go back to Louisville when Petrino leaves so the agent is probably trying to get Brohm's part of the buyout removed.
(2) Purdue "loaned" him the $900K for the WKU buyout while agreeing to forgive 150K a year. Have to assume that figure is completely forgiven.
(3) Brohm's maximum is supposed to be $3.3 million per year. From how I read his contract, Brohm's base is only $1.5m, however. Some of the incentives are easily reachable such as the academic requirements. Others are laughable (e.g., $600K if they reach the CFP).