1. Since the property acquired in the name of my grandfather was based on earning of the family and not he alone was earning during his lifetime. So the property should be equally/shared by all members and why can't be given to both brothers (with consent of grandmother and sisters). Is this not injustice if a property acquired through joint earning of Grandfather and Grandmother is divided on the wishes of Grandfather only.
You are changing the question itself from the first post to second post. Earlier you said it was bought by income of husband and wife whereas now you say that the property acquired in the name of my grandfather was based on earning of the family and not he alone was earning during his lifetime. Which one is correct. However what is the proof of others contribution to the purchase of the property, does the 'others' claim a share in the property on the basis of their contribution?
actually the grandfather would have been the head of the family ad his saying was binding on all the family members as a custom prevailed that time hence nobody raised any objection t it, however being the third generation you do not have any rights in the property, why are you so much concerned about somebody else's share when that somebody is not interested to litigate the issue. In fact this issue had an answer with your grandfather when the question was put to him by the so called eligible heirs to him. The justification issue has an answer with your grandfather alone for which you are not entitled.
2. Since he was behaving badly during the last 15 months with Grandmother. Why we can't claim in court that he is medically unfit (All of us i.e. Grandmother, one brother and two sisters are ready to file this fact). The court can accept it and order/ask for medical examination so that we do not become victims of this un-justice.
Your grandmother can file a domestic violence case against him and also can claim monthly maintenance from him. that is all she can do, his medical condition has nothing to with the share in the property. The property becomes self acquired property of your grandfather, so instead of aggravating the issue and losing the share in the property which may come in the normal course if there was no quarrel, better adopt patience. to achieve goal. There is no injustice as per law, so there is no question of victim too.