Property Dispute Query Inherited Property

My Grandfather who passed away in 2003 has a residential property of 6000 sqfeet.. he has 3 sons and 3 daughters of which the elder son and second are not alive. Also my grand mother passed away in 2005. My father is the second son who stays in the same residential property and has no other house. May father has been maintaining the property and has been paying for all the bills and taxes for the last 20 years also he was only person to take care of my grand parents till thier last breathe. Now the other share holders especially the two daughters forcing my father to sell of the property and take their share to which my father is not willing to do so considering his age (72). Is it possible that the other share holders can take legal route and force my father to vaccate the property? As my father did so much, can he legally claim for a higher or major portion of the property? Can ther share holders claim for a partition of the that house and occupy a portion? Need your help