Harrassment by in laws of sister

Dear sir my sister was married in udaipur in jan 2012. month b4 the marriage we were told that the groom has lost his job (which was in IT SECTOR). My sister herself being working in same sector told that this must be temporary so we agreed.we spent more than what we could affordand met all their demands, later after marriage it was revealed that he was not working only for long time (nearly 2 yrs approx dont know exactly) but then it was too late. my sis also has to leave her job. than after one yr finally he went on a contract job to US but came back in dec, again remained at home doing nothing. in the mean time they kept on indirectly harassing my sis taunting that we(my family) have not given enough to them also in 2014 when she gave birth to a girl child they indirectly gave indications that they are not happy. though directly never said this, indirectly always kept on saying that my family did not spent enough. after birth they did not even send my sis to home, and started ignoring us at times disrespecting my parents. my sis kept bearing patiently. then in mar 15 he again manage a contract to US and went again with the promise that he will get settled now(my sis insisted that it time and family has grown up now). She then insisted to meet all of us as she thought she might shift to US and came home for a month, but suddenly in jul he gives a call and says he is going to come back again. and came back in aug 15, now says that he will not work again will find a job when facing financial problem again and says she and my family don't have any right to tell him what he is suppose to do. and has been misbehaving with my mother on phone. he is not ready to speak to me also. i have sent him many msgs. i work in nagaland and not at home. my sister took a stand and told she will not return until he finds a job. but then he started blaming us for kidnapping her daughter(her is the word he used). and he refused that i will not change neither will find a job and saying that he will come and take her soon. my parents are old and very simple, please advise thanking you in anticipation, my family stays in moradabad