It appears that Yash's mother must have died when he was v.small and the King married the present Rani Ma and she brought up Yash and instilled good values in him.Whereas Aryaman was brought up by Daima and we all can see wht type of teachings Daima gives Aryaman. It is said that mother is a person's first teacher and for Aryaman Daima was like mother and may be Queen mother didn't get time for him. Hence the difference between both bros.