I would not use any eye medicine intended for humans. It's possible that it's a very bad herpes infection, and occasionally vets treat this particular eye condition with antiviral meds, which can be pricey.
As my vet always says, eye problems can get better quickly, but also can get worse quickly as well.
If going to the emergency vet is an option, I would definitely take him. I don't want to scare you unnecessarily, but he could have an injury to his eye, which could be very painful, and potentially lead to the loss of his eye.