If we really believe these things about PR, there is no answer but to fire him asap. Personally, I believe that would be the correct move.
It isn't about Lanning not wanting to play. I'm sure he'd jump at the chance. It is about what Paul Rhoads and staff will do to his psyche if he is the starting QB. Rhoads will ruin Lanning like he ruins every QB if he turns his attention towards him.