My mother's father had a house in Hosangabad (M.P.) and it has 5 seprate portions. 2 portions having

My mother's father had a house in Hosangabad (M.P.) and it has 5 seprate portions. 2 portions having joint let bath area and 1 seperate portion having individual let bath area on the ground floor and 2 portion on the first floor having joint let bath area. My grand father(Nana) had done a registered will and as per that will ground portion are for 3 daughters and first floor portion for 2 sons. My mother passed away on 31st dec but before that the individual portions are transferred on the concerned person's name. My Mama(mother elder brother) also passed away but his wife stays alone in the house.

She stays at my mother and her elder sister(my maasi) portion at ground floor. My mother elder sister filed a case against her(elder brother’s wife) to vacate the portion but later on we discovered that she had done a will with 3 witnesses by my nana’s wife in which its mentioned that ground floor both portions belong to her. Now my nani is also no more. My question is whether a registered will (by my nana) can be changed by his spouse (Nani) and as my mother demised her portion will belong to his husband or children.