First of all, saying "don't teach me anything" comes across arrogant, whether you intend it or not. Secondly, instead of giving a vague answer that this practice has been going on in India for 1000's generations, you could have instead pointed out that it's the position of the Hanafi madhbad. Not everybody associates India with scholarship. Even though I know the Hanafi Madhab is well established in India, I did not at first occur to me that this is a position in the Hanafi Madhbad. It took me a couple of seconds to ask myself, "Is this a valid position in the Hanafi Madhbad?", to which we got an answer. Quite frankly, the first that came into my mind after hearing, "That's what we do in India", is a cultural practice precisely because the wording was so vague. You could tell him that there is a scholarly difference of opinion on this matter when it comes to the four Madhabs. However, if he goes on to deny the validity of the Hanafi school, then you could point him out to some Hanafi resources on this matter. If that does not work, then you should just ignore him.