Help! Son Admitted to IIT Kanpur and IIT Hyderabad - Which to Choose?

Hi sir, We want to get some guidance for college admission, My son has got IIT Indore Mechanical engineering in JOSAA 1st round He also got seat in IIST Trivandrum Kerala - Electronics and Communication Engineering Avionics. Which college will be better to join IIST or IIT

Dear Sir. As parent, I have two questions - first is which engineering course to pursue and second is which institute to get admission - based on some trails mentioned below. My son registers for JEE 2025 Session II, BITSAT 2025, VIT 2025, COMEDK UGET 2025, MHT CET 2025. As plan-B option, he has also registered for IISER Aptitude Test (IAT) 2025, NEST (NISER 2025). Score in JEE Session I is 78.43 Percentile (Physics 90.76, Mathematics 84.1 & Chemistry 15.44). He has no interest in chemistry - which is also reflected in subject wise percentile. However, he has keen interest in deep-thinking, particularly in physics. Based on the association with my son, I clearly understand that his ability not at all aligns with his poor performance. As regards career, at present, he has strong desire to work in ISRO. He often share his idea with me by saying "I don't want to pursue Computer Science and thereafter money to become rich but I love to explore Space/Aerospace and so I want to join ISRO. But at his young age, my son is too immature to take the decision that which course will help him to land in ISRO. My son, somehow, comes to know that ISRO absorbs mechanical engineer through ICRB examination. Based on this information, he wants to pursue mechanical engineering. But, according to my opinion, as of today, as mechanical engineering has less scope in job-opportunities, it might be a risky choice. So, to remain on safer side, I insist him to pursue Electronics and communication engineering. My idea is if he pursues Electronics and communication and finally gets absorbed in ISRO, it is fine. Otherwise, (if not in ISRO), one can find job in other sectors (Government/ Private) as a Plan-B option. But with mechanical engineering, as of today, it may be difficult to find a suitable job of one's choice because of less job-opportunity in this field. Please suggest whether I am right or wrong in making this decision. My second question is which college should I choose for my son, based on his test in academic? As with this low percentile, my son will not be able to bag a seat in reputed government institute like IIT/NIT, so I decide to get his admission in some reputed private college/university. In this regard, I hear from people that when it comes to quality of education in private institution, South India is better. So, I decide to get his admission with Electronics and communication in some reputed college/university in Bangalore (although I and my son belong to north India). So, please suggest me whether I am right or wrong in making this decision. Also, please suggest me the name of reputed institute based on this perspective. Your valuable suggestions will my son to navigate in choosing his career path with desirable engineering course from a good/worthy institute - where he can flourish/nurture his taste of his choice.