Your son Karthik has Lagna in Sagittarius and Moon sign is Virgo. Moon and Saturn are 17° apart from each other. Lagna sub lord Mercury is also the cuspal sub lords of 3rd (basic intelligence), 6th (sickness, success in all undertakings), 8th house (tensions) and 9th house (higher intelligence). Mercury is located in 8th house with Sun (13° apart from each other) . So blending all these, he will be stubborn and likes costly, luxurious life. He will have unnecessary tensions and sometimes gets disturbed and has to visit hospitals.
His 2nd cusp (speech) sub lord is Saturn in 9th house, in the star of Moon in 9th house. He will not speak much but he will be excited too much and speaks bad words. He will have anger issues. He will not spend much, suddenly his expenditure would be lavish.
Education : He can have education and get on well. The results would be beyond your expectations. He may say 40pc, but he would get more. He maintains his status.
If you have faith, please ask your purohit there to do abhishekam to Lord Hanuman with Manyu suktam. You drink him up with the theertham. This should be done for 7 consecutive Tuesdays. He should be cautious in journeys or may visit hospitals during 09-7-2026 to 02-9-2026. In 2023 also he might have visited hospitals.
Good Luck
JVS Rao (KP system follower)