Mental harrassment

Hi - We are Jain and my sister has been married in Sharma. This is love marriage. Ever since the start of relationship, i.e., pre-marriage, my sister's father in-law and mother in-law has been commenting on everything that we do as a responsibility like giving on various festivals. Her mother in-law would call my mother and use uncalled language about the amount and volume of gifts that we give. Father in-law would every time say that we don't want anything and then would say that as per their culture, we need to give XX amount of gifts. On the birth of my niece, her father in-law said that on this occasion we should be giving 11 pairs of suits and cash is involved, etc. Mother in-law said that don't give at this time as we are busy and thus we gave less volume and amount to all as a token of happiness and that was show cased as everything that we gave and insulted my parents. She didn't took care of my sister after baby's birth and forced her to come to our house after 12 days itself. They want to get separate but her parents in-law are not letting that happen and do emotional game. My Jiju is standing strong with my sister in her favor and supporting my sister every bit. Last thing, my Jiju's sister and her husband including their children also stays with them which is basic problem of all this. When we visited them for the first time before marriage, we were told that their house is getting renovated and they would shift to their house before my sister's marriage which never happened. Is there anything that we can do legally to give my sister and her husband a little peace?