Property issue

After my grandpa death his flat was sold and his 4 sons and granny got the share and we shifted to other flat which was also in the name of my grandpa.. we were searching for our own flat so my dad kept his share in my granny's account.. my granny after a year or two without my dad's consent bought 2 flats in a nearby area and shifted there stayed for 4-5 yrs and sold that flat and gave the share to her 2 daughters out of 3 and kept the rest amount with her and made a comeback to where we were staying.. now she is saying that she will not give my dad's share what profit she earned with his money when she sold the 2 flats and gave it to daughters.. she wants to sell the current flat and give on share of the lefr daughter out of 3 and she wants her share more than what is in our islamic law and she is saying she wont give my dad his share with profit she earned because that was my dad's right without consent she bought and sold the 2 flats and gave the share to her daughter and kept the rest money... She is saying she will only give the money what my dad kept in her account at the starting after grandpa death... Please suggest me what can i do to get my dad's full share in the house.. can i stop the current sale agreement which my granny has done with the buyer party she is selling this flat.. need some serious advice