query is this: if my son does the IB diploma course from an indian Ib school then what would be the procedure to get into IIT for Btech??

my son is in his 9th ICSE he wishes to do iit but the trend of IB is catching up. if he takes up IB diploma he wont have the time for his IIT-JEE preparation done seperately. so does doing IB give him a direct entry or is there any other kind of exam do the IB students r required to do .pls guide