Rajesh,
from what I can see per classical astrology, your son has a great combinations in his chart including
* 10th lord Moon and 9th lord Mercury conjunct in 9th house (mercury being retrograde becomes weak)
* 2nd and 7th lord Mars in 11th house
* 11th lord Sun in 10th house
* Yogakaraka Saturn in 5th house (Saturn being retrograde becomes weak)
He has started Saturn Mahadasha from 22/9/2014 which is placed excellently in 5th house in nakshatra of Mars and Sun . Sat-Sat period from 22/9/2014 to 25/9/2017 ideally should be good period but Saturn retrograde brings down discipline and structure. He will start Sat-Mer period fro 25/9/2017 to 4/6/2020 which looks worse as retrograde Mercury is placed in star of Jupiter with Venus as sublord. Chances of success in competitive exams seems average.
Jupiter coming into ascendant from Sep 2017 and Saturn in 3rd house should provide temporary relief.
His 9th house of teaching and import/export is strong along with 2,7,11 houses of business. Saturn placed in 5th house encourages creative pursuits as well. My suggestion would be consider creative fields of teaching, travel, export/import advertisement/communication and ideally he should do his own business (he will excel in that).
Neelam or Saturn beej mantra would do good for him. Saturn period till 2033 is best period of his life and Saturn will give good effects only if he puts in his karma/100% effort.
God bless,
Astrologer Deepak