With a Percentile of 98.99 in JEE Main, your son has fair chances of securing a CRL anywhere between 11-11.5k in JEE Main. Assuming he is a General Category Aspirant, he has fair chances of securing a seat at one of the following IIITs

IT at IIIT Lucknow, Computer at IIIT Vadodara, Lucknow, Pune, Surat, Nagpur, Bhopal, whichever campus is in vicinity of your place, he may take admission. All are equally Good.

However, he may consider GFTIs like IIEST Shibpur and BIT Mesra, which are much better Ranked have excellent infrastructure and placements. He'll get IT in both these TOP GFTIs and CSE at IIEST at par with the Top NITs.

For more information and college prediction do follow the link below

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer