Hi Friend,
First we will see Hindu Succession Act.,
Hindu Succession Act
General Rules of Succession - Male Hindu
The property of the male Hindu dying intestate shall devolve in the following manner
Firstly upon all the heirs, being the relatives specified in Class I;
Secondly, if there is no heir of Class I, then upon heirs being the relatives specified in Class II;
Thirdly if there is no heir of any of the the classes, then upon the agnates of the deceased; (one person is said to be agnate of another if the two are related by blood or adoption wholly through males) and;
Lastly, if there is no agnate, then upon the cognates of the deceased. (One person is said to be a cognate of another if the two are related by blood or adoption but not wholly through male)
Now we will see class I heirs shares and who are there in Class I heirs as per Hindu Succession Act
Class Ist Heirs
Son
Daughter
Widow
Mother
Son of a predeceased son
Daughter of predeceased son
Widow of predeceased son
Son of a predeceased daughter
Daughter of predeceased daughter
Son of predeceased so of predeceased son
Daughter of predeceased son of a predeceased son
Widow of predeceased son of a predeceased son
If you check that your sisters do have equal share in the property. Still you want to sell the property and builder is ready to take property its well and good. If he is willing to give you all remuneration at once. Otherwise you both means purchaser and seller will be in trouble.
If you can have family meeting with a siblings and try to talk with your mother, let your mother handle the situation to get NOC for selling the property, you can do here compromise or settlement of NOC otherwise all brothers and sisters have equal rights as per law in the property.