Property dispute

Give a Legal Notice to your Brother.  About un authorised construction in Joint Famly Property.

dear sirs one of brother is not wordly wiser man and his eldest brother purchased a stamp paper in the year and he took amount of rs 4 lakhs at that time from his friendin the year 1992 and in the year 1996 he took the signature of his brother on the said stamp paper with an agreement of stating that his brother is willing to sell his property if he does not pay the amount at the end of year 1996.

at that time this his both daughters are minor girls aged about 7 years and 5 years old.

being  not a  wordly wiserman his elder brother taken all the amount of 4 lakhs and got the signature of his brother.

now the major daughters filed a WP in HC and got the status quo order.

the so called stamp paper is with over writing.

what are the case laws to protect the property of the daughters please explain   

the agreement of sale was done without the knowledge of this illetrate brother and took the money on behalf of him by his eldest brother with a most criminal mind and wanted to sell of his younger broteher property without the conquerence of his minor daughters