In case your grandfather has already died then the ruling of your deceased grandmother’s house and her other property is that her entire property shall be divided into 98 shares, after paying due rights preceding inheritance provided the detail of the heirs is correct. Out of the total her each daughter (your phuphis) shall get 24-24 shares, your mother shall get 6 shares, 14-14 shares shall go to both of you (brothers) while your each sister shall get 7-7 shares. The newasa (son of daughter) and newasi (daughter of daughter) of your grandmother shall get nothing as per the Shariah. They shall get nothing from the inheritance. The detail of division is as follows:
Daughters (Your Phuphis): 2×24=48
Your Mother: 1×06=06
Sons (you and your brother): 2×14=28
Daughters (your sisters): 2×07=14
Allah knows Best!
Darul Uloom Deoband