Hi Khatera, from my point of view, your husband should go back to Afghanistan and submit his passport to ISL when he get PPR, it is normal procedure and everyone gone through this process apart from those who were in India from beginning, if your husband want to send an amendment letter regarding changes in his address at this critical stage, have you ever thought about impact of it? such us delay in your application, probably they ignore your email or response late, choice is yours, I just gave you my opinion, your case already concluded i suggest that you should not be in hurry and do not change anything. also it does not matter either your husband want to submit his passport from India or ISL, the time frame for issue of visa is almost same.