I doubt Jeff Brohm would ever leave PU for UoL. He is going to be one of the hottest coaches in the country at some point, if not creeping toward that already.
Next year alone; LSU, UCLA, Nebraska, TENN, TX A&M, etc etc, could all be looking. You don't go from being a HUGE success at PU to UoL (a somewhat lateral move at best, even with his family history), you go to a top school/Blue-Blood.
I can see him leaving at some point, and hopefully leaving us in prime time shape, but not for paltry/ghetto-bird UoL (unless his career at PUR is basic, and he just wants to go home).
edit; not saying he'd leave next year for one of those schools I listed, just giving examples of historic "top schools"/Blue-Bloods that could be looking next year, and that opportunities to jump to an all-time great program are common after just about every season. No need for him (when that day comes) to settle for shithole UoL if he truly wants to leave (DON'T GO!!!)