Inlaws and husband abusing and torturing the girl she has a child now

we belong to Hindu (Bania) family. My sister married last year in July, at the time of marriage, we fulfill all the needs of the family like jewelry, cash, etc but when our daughter has gone to her in-law's house all went wrong. They started abusing her, making demands on every little occasion. her husband himself abusing her as well as her in-law's. after one month the sister is pregnant. husband openly drinks in front of our daughter and abusing her. when she told us all the matter, we involve and ask her father-in-laws that why are you doing this, they don't have any answers. we talked to husband then he says my father is not in his mind let me shift somewhere else. they moved, husband came but not even with his single cloth. after that he beats our daughter very badly, when we involve again they still don't have any answers, now in month of april she gave a birth to a girl child, and NO-ONE shows up.... Now our question is that what we have to do and what are the options we have.