Hello, Marlo
How old is he?
How long has it been this way?
Is there is a discharge? if so, what color?
Thank you for the extra information.
Use some plain saline to flus the eye out good. That will remove any debris in the eye and also sooth it a bit.
If still continues to weep afterward, I would make an appointment with your vet to rule out an infection in the eye. There are several different eye infections that cats can get from conjunctivitis, Keratitis, upper respiratory infection, and so on. None of these are big deals, but do need treated properly to avoid complications later. Many eye infections can lead to partial or total vision loss if not treated. 99.9% of eye infections just need an oral antibiotic and maybe some eye ointment as well.
Sincerely, XXXXX
Expert in cat behavior and health
Expert in cat medical and behavior issues.