Dada ki property pota ko kaise hoga ?

Contact a local advocate.  Your dada is living and it appears that your dada is maternal grandfather.  There are several facts to be looked into the Hindu partition. Your mother is having exclusive rights first and not grandchildren.  Generally, the last rites must be performed by husband side relations in Hindu Tradition.   Because they have performed the rites, there is no law, that the entire property exclusively belongs to those who performed a religious duty.

Firstly it is your maternal grandfather's property.

He is alive hence he is the authority over his property because he is the absolute owner of the property  that is lying on his name.

You have your mother living who is the daughter of your grandfather.

In fact your mother herself is not having any rights in the property not at lest during the lifetime of your grandfather.

Your mother's second marriage will not disentitle her to inherit her deceased father's property if he is reported to hav died intestate.

Even then you are a third person to the property especially when yor mother is alive.

Therefore whether you carry out the last rites of your grandmother or not, you are not entitled to any share in your grandfather's property as a right.

If your grandfather is supporting his brother's daughter in law and is willing to transfer the property on his name to her then nobody has any right to challenge the authority of your grandfather including your mother. 

Since you  have no reason to claim even a share in this property, you cannot exercise anything in the name of right to this property.

It is not an ancestral property to you hence you cannot do anything about it except to watch the same as a silent spectator.