The Wife of your elder brother is bhabhi for you. In India, Men call friends’ wives also as bhabhi. In English, it’s Sister in Law.
Sister in Law
So if someone asks Bhabhi ko English mein kya Kahate Hain to then answer is Sister in Law
In fact, after marriage in Indian society, IN-LAW is used as a postfix to all the relations of the groom for the bride side and same for the bride to groom side.
Like father-in-law, brother-in-law, sister-in-law, mother-in-law, son-in-law, daughter-in-law.
Wife’s sister husband ko English me kya kahte hain?
Sister in Law