Most likely the guy will be trespassed from the amusement park - fancy legalese for banned.
It's up to the pollice and prosecutor to determine what, if any, criminal charges will be filed.
Both moms are going to find lawyers and sue the heck out of the guy. That may happen before or after a decision is made on criminal charges. The guy will, if his lawyer is smart, work out a settlement.
[major rant ]It clearly states the guy pulled the trigger. Therefore the gun did not "go off"! It was fired. Even if the guy did not intend to fire it, he did fire it. He even said so!
How long has it been that handguns have been manufactured with some sort of drop safety mechanism?
And how many more times do we have to remind folks that if their gun falls, do not try to catch it before it hits the ground? Better some serious scratches than, like this guy, getting your finger inside the trigger guard. When we catch something the physical act involves closing the hand. If your finger is inside the trigger guard when you close your hand there is a high probability you will be pulling on the trigger, which will cause the gun to go bang.[ /major rant]