Child unintentionally shoots father in the back in Walmart parking lot

Monty Wheeler was at a Walmart in Russellville, Arkansas with his son. According to reports:

It was determined the man had accidentally been shot by his child. While the child was attempting to enter the vehicle, the child accidentally grabbed a hold of a loaded shotgun, that had not been secured, to help pull himself into the truck.
While grabbing the shotgun the child accidentally pulled the trigger and caused the shotgun to discharge and strike his father in the back.

Wheeler was taken to the hospital where he was listed in stable condition. No one else was injured in the incident.