Dear all
Please advise regarding procedure and requirement of legal documents in following situation
My sister, a widow along with her children is living with her mother in law in a joint family in one portion of a house since last 30 years. The house property exists in the name of her mother in law on a plot of approx 225 sq yards on lease. The mother in law wants to divide the property/ land between her living son and my sister in equal proportion i.e. 50% :50% in her life time only as she is getting old. While her son and his family are insisting to break the entire house as he plans to construct a three storied house on the plot considering future requirement of family and has offered my sister that she will be provided ground floor in the new construction and she should contribute money in construction of ground floor. Though this meet my sister’s family requirement too however she can not afford to get the new construction of the first floor on her own as she has already spent a sizable part of her saving in adding one room to her portion of house recently. Thus, she has asked to reduce the land share in her favour. Her brother in law has worked out that she will have only 40% of share in the land for having ground floor while he will keep 35% and 25% share of land for the first floor and second floor. He will construct the entire house incl ground floor. However if the cost of construction of ground floor exceeds cost of 10% of land, as reduced in her share, then she will have to contribute excess cost accordingly. He is asking her to vacate the house so that he can execute the construction, while no legal document have been made.
What legal documents should be made so that her brother in law may not go back on his words?
(a) A family settlement / Partition deed to decide ownership share first ?
(b) A contract later once she gets ownership share decided.
(c) Or any other document?