Usually the intense part of the heat only lasts about 3 days. Your boy should relax a bit in a few days. But don't let your guard down. My vet told me that usually they bleed hard for 9 days and then they are VERY fertile for 9 days. Breeders will tell you that the window is about 3 days.
But it seems like if you have all your ducks in a row and WANT to have puppy that window is very short. But if you are trying NOT to have puppies, it is a whole different story.
You will just have to wait it out.
I would NOT spay your bitch while she is in heat here or in India where you are. The surgery becomes much more complicated as there will be a lot more bleeders to tie off. She will be under anesthetic for much longer and there can be serious complications to anesthetic.
Just keep them apart. It may be helpful to purchase a couple of crates.
Jenna, RN CGC & Babs, CD RA CGC HIC
Heidi, RA CGC
SG3 Odessa, SchH1, Kkl1, AD
Ninja, RN CGC & Milla, RN CGC
Joy, Star Puppy, RN CGC
Dolly CGC & Bear CGC