The 5.7x28 is not even close to the 5.2x47 (AKA .204 Ruger)
I would keep game size to coyote, maximum and ranges fairly short, for the 5.7
They generally use light bullets with low ballistic coefficients, and sectional density, and the muzzle velocity is not very impressive. It's essentially the .223 'downsized' into a pistol cartridge.
It could be plausible to use it for pigs at very close range, but I WOULD NOT recommend it unless you're using AP ammo and limiting yourself to headshots. And still, there are obvious choices which would be better, for that task.
I really hope this guy isn't using his semi auto to empty an entire magazine, on game that is too large for the cartridge and caliber he is using.