Property inherited upto 4 generations of male lineage (i.e., father, grand father, etc.) is called as ancestral property. The right to a share in such a property accrues by birth itself, unlike other forms of inheritance, where inheritance opens only on the death of the owner. what has been inherited by their respective predecessor.
The Supreme Court of India has said that women do not have the right to inherit ancestral property if their fathers died before September 9th, 2005. The view of the Supreme Court is that amended provisions of the Hindu Succession (Amendment) Act, 2005, do not have retrospective effect. The father would have to be alive on September 09, 2005, if the daughter were to become a co-sharer with her male siblings.
First you have to check the property is comes under the head ancestral property ?The rights in ancestral property are determined per stripes and not per capita. This means that the share of each generation is first determined and the successive generations in turn sub divide what has been inherited by their respective predecessor.
In your case, the property is not comes under the head "ancestral property". So after the death of your grandfather the legal right over the property transfer to his legal heir his son and his wife. After death of your father the right over the property transfer to your mom and sisters and brothers. If the house is in dilapidated condition then repair the house. But remember that you have to settle the matter amicably.