Thanks for writing your query.
After reading your post, it seems that your son is having blocked nasolacrimal duct
Usually this condition improves by itself after the age of one years.
You can massage
the area 2-3 times a day.
Using your clean finger, rub the area from inside corner of the eyes towards the nose. This may help open the tear duct.
A blocked tear duct that doesnot improve, may need a minor probing procedure.
You should get his eyes examined by an Ophthalmologist.
I hope this is helpful to you.