Who can claim property of unmarried sister

My wife who is youngest among 4 sisters and one brother. My elder sister-in-law (unmarried and no legal heir are there) was expired leaving her house and land on her name without any will and Term deposits with nominations. 1. Who are the legal heir for my late sister-in-law's property, (father-in-law and mother-in-law were already expired before her). 2.Term deposits got accounted to the nominees (children of all 3 sisters). Will this have any legal validity or any legal repercussions? 3. whether all sisters and brother gets equal share of property. 4. How to solve this, because my brother-in-law is asking equal share in term deposits as well which are already got accounted into nominees account. (This i am writing on my wife's behalf, who is the youngest amount the remaining sisters and brother, all are got married). Kindly advise.