Always keep your muzzle pointed in a safe direction.
That said, a “safe” firearm is one with a mag/tube whatever out, action locked open, safety on, unloaded, preferably with a chamber flag in, firearm grounded with no one touching it.
So, how many safety rules to he have to break to get shot?
May not have been anything to safely wedge the firearm into (like a forked tree trunk or a training bag) to ensure it was pointed in a safe direction. But if it's on the ground, it ought to have at a bare minimum the action open and the safety on. And if he was done shooting for the day and collecting the decoys, unloading the thing wouldn't have hurt either.
I don't ever put down a loaded gun except on the staging table at Cowboy Action shoots. And there's a Range Officer and three spotters keeping an eye on it (and no stray dogs).
Always keep your muzzle pointed in a safe direction.
Are you talking about the dog or the gun?