Yes, what punishment do you think your coach should face for that? Be honest.
Remember, he saw an opposing player get hurt, had no idea if he was hurt or the severity of it (by the way, lots of guys get dinged up for a play and return and lots of guys high five).
He fell down just moments after the injured PSU player, so clearly he doesn't know how bad it is at that point. It is more than fair to say that it can take time to figure out just how serious an injury is, which I am sure you agree with. Remember that for years a concussion was just "getting your bell rung" now we know that it can actually lead to death.
So, in your honest opinion, what should the consequence be?