Your son has no Kuja dosha. Kuja is in the third house, though in the Rasi chakra it is in the 4th house. However his 4th, 7th and 12th houses are very weak and it is very unlikely that he will have a happy married life unless you get an excellent matching horoscope. He has a strong Pravarjya Yoga too.
Read my blog Navagraha Astrology Online for more information and how to check for a scientific horoscope matching.