My mother's share in her father's ancestral property

Firstly answer the following questions :

Where the land is situated?

when the will was made?

Hi,

You have not stated in your query whether the will made by your maternal grandfather in favour of two son has been probated yet or not.

If not, then your mother or her sister can make application for objection in the probate proceeding under the Indian Succession Act. If probate has already been granted, then your mother or her sister have no right to place objection in this late stage.

Hi, the plot is in West Delhi, Tilak Nagar and the will was made sometime in early 90's (do not have the exact year)

Hi, i am not sure what probate means but i know that both my mother and aunt went to he cout and issued a statement(don't know if that is the right word) stating that they are also he children of my maternal grandfather (his name) and that the house should not be sold without their consent. Does this information help in any way?

Prima facie, a claim can not be made by your mother/sister on the said property since it was already bequeathed under a will to somebody.

Secondly, do go through the terms and conditions of the grant of land which was made by the State to your grandfather. 

i am a widow i want  my share of agriculture land and ancestral house transfered in my name which is still in name of my father in law  who also is dead even my both mother in laws are also dead   my father in law had1 son from frist wife & 4 son ,4 daughter from second wife  even their 1 daughter is dead so how do i proceed

File a partition suit.