Cockatiel eye situation- Please help!!?

first off, he's not my bird for me to take him to a vet. The owner isn't doing anything about but i want to see if i can help him anyway.

so i looked at his eye, and its red and kinda puffy. it looks like there is something on it. it's not always there, it moves around. at first i thought it was a foreign object (maybe a feather) so i put some warm water on and around it to see if it will come out with the water. It didnt. i tried to help it out by coaxing it with a warm tissue but a gentle tug showed that whatever that thing is, is definitely coming from inside his eye. it's attached to something inside. possibly to the lower/inner eyelid. it's either something that got in and got really stuck to something and wont come out, or something that is in and isnt even supposed to be out. I think it's the latter.

Anway, im trying to tell my boss to take his bird to a vet, but he' snot budging saying he's had birds before and these things just go away on their own. But the bird keeps his one eye closed all the time. he's an adult male, about 8 years old. otherwise he is alert and healthy, eating and pooping like normal. he wont come out of his cage but i think thats cuz he has such limited visibilty. his behaviour otherwise hasnt changed.

ANY help will be good or if anyone might know what that thing might be on his eye? anything to keep him going or help him.

Thanks