He didn't expect to be considered for the Head Coach job.
He wanted to stay on the staff and it is apparent he has been told that won't happen. He waited around through Jeremy Pruitt chastizing both he and Graham for taking the pay cuts because he loves the university and wanted to stick around. Fulmer made him some assurances that he knew wouldn't be honored once Phillip was fired, but he turned down other opportunities anyway to wait and see who the next coach would be.
He and Heupel have some beef, apparently, and separate from that point, it appears Heupel has another coach in mind for the WR coach spot. That's life in this business. But it does come with some hurt feelings for a guy who has never felt like he was truly appreciated here.