Your Son was born under a Gandmool Nakshatra by the name of Revati, I do hope that you must have done the Gandmool puja at the time of his birth. Presnetly he is running the Vimshottari dasha of Ketu and Mercury which are not placed well in his chart. You can do remedies of Ketu.
1. He should wear Moti on his right hand ring finger
Moti in the neck is fine. Ketu mahadasha is going on and antardasha of Mercury. Ketu mahadasha will complete in January 2016. Ketu in transit will enter Aquarius in January 2016 which is the 8th house as per his horoscope. Ketu in 8th house is not good. Therefore he should be careful while driving, on the road, while catching bus, working with sharp tools. Urine related problems can be there.