Please share a picture of his eyes. That would be really great and will help all doctors to provide better treatment.
However if u have noticed it since just a few months,
It can be due to eye allergies. A disease known as spring catarrh can make the eyes appear yellowish or muddy in colour.
Start eye drop Bepofree - 1 drop in both eyes, twice a day.
Eye drop - cmc, 1 drop in both eyes, 4 times a day.
Next Steps
Buy these eyedrops and start using them for now. If the symptoms don't improve, please visit an ophthalmologist nearby.
Health Tips
Use ice packs twice a day