Our son was diagnosed as stage IV NB when he was 2 yrs + 11 mths. We currently reside in Tokyo, and initially we considered seeking treatment outside of Japan, since our preconception was that the US had the most 'effective' and 'agressive' medical treatments. We have been fortuate enough to have been able to have the leading doctor for NB in Japan from the very beginning, but we also did our share of homework, and we decided to stay here for the following reason.
I guess both the good news and the bad news is that basically all of the protocols conducted in developped countries are more or less on the 'same' track; obviously the tiny bits and pieces might alter according to each protocol (such as medication, dosage etc.), but in general, they are quite similar. From what I have seen, the protocols in the US, Japan, and Germany are quite similar, and the results don't seem to have dramatic differences. Thus, we decided to stay here to do our son's induction therapy. Although I am not sure what kind of protocol your son is on, perhaps you can do some research on the protocols conducted elsewhere. The handbook on this website has a comparison chart on protocols, or you can even ask your oncologist for some information from medical books. You can even seek for a second opinion with other pedriatric oncologists in your own coutnry. In case you want to change your current protocol, your doctor should assist you on that - one of the most important thing is that you can find a doctor who listens to you, says 'yes' when he can, and 'no' when he can't (of course, after giving you a good explanation!), and most of all, someone whom you and your wife can trust.
I personally feel that as long as you can modify the protocol with your doctor (if necessary), there is no need to leave India. If this still doesn't make you feel at ease, and yet financial conditions don't allow you to travel abroad, try to find the BEST NB oncologist in India ( I am writing this under the presumption that your insurance covers you as long as you are in India).
There are other 'new' treatments going on, but the avialability changes according to each country - you can also consult your oncologist regarding such treatment options.
I know it is not easy to make treatment decisions, but I wish you all the best.