Lions vs Cowboys: Was he an eligible player or not??

Jim Daopoulos is very familiar with being on the football field and refereeing NFL games for 23 years, so what’s his opinion on what happened during the Lions and Cowboys at the end?

What happened at the end of the Detroit Lions vs Dallas Cowboys game where a player tried to make himself eligible, but apparently didn’t? What SHOULD have the player done? Is this on the Lions or the refs when it comes to who dropped the ball? What should've been done differently?