Widow being forced to leave the house by in laws

Hi , My sister is a widow , her husband demised in 2012. They were married for 14 years and have 2 littler children. My sister is working in some temp job and earns just enough to sustain. And she is not being supported by any one at in-laws. Now her mother in law and along with her 3 daughters (who are married and well settled) is forcing her directly or indirectly leave the house by creating unhealthy environment at home and on daily basis she is undergoing traumatic situation at her in-laws home. My bro-in law who expired does not own the house he lived in, it his mothers. Its my sisters mother-in-laws property, we do not know if its self acquired property or was it given to her by her father(mother in laws father). Now our problem is 1) We do not want her to leave her husbands home, as she cannot afford to live in rented home 2) She undergoing huge pressure, they are coming up with new rumours daily to torture her, we guess if my sister is unable to bear it and leaves the home , they can split the property at their will and use it .. 3) Can she claim right on behalf of her demised husband for the properly for her children education 4) If property is self acquired property of my sisters mother-in-law and if she decided to split the property among her daughters, is it as per law right, and can my sister claim right for this property 5) If property is not self acquired property of my sisters mother-in-law ( property given to her by her father) and if she decided to split the property among her daughters, is it as per law right, and can my sister claim right for this property. 6) Can we report this incident as domestic violence by her in-laws and their daughters. 7) My sister son and daughter are minor's can they claim some part of the property to live in or for education.