Hi J.. My daughter, now 21 months, recently had two surgeries to correct the same problem. Hers were constantly pussy for her first 19 months. The first was a probing to open the duct, which ended up not working. The second, they placed a stint in the tear duct that will stay for 3 months to help the duct "grow" open. It's been a month since her second procedure and her eyes are crystal clear!
Both procedures took less than 45 minutes to complete. The hardest part was putting her under anesthesia but that was also very quick (less than a minute). Recovery was also amazingly fast. She was discharged within 3 hours and back to normal within 6. It was amazing to me that she had surgery in the morning and was home running around with clear eyes by evening. The only side affect I noticed from the second procedure was a bloody nose, a lot of blood!, but nothing from the first. If your son is having the probing try to put your mind at ease. It is a fast procedure with very little side effects or down time. Even the stint placement was a lot easier than I though it would be and she doesn't seem to know it's there. It is visible in the corner of her eye.
I hope this works for your son. Good luck and best wishes.
Amy