Refuse to vacate 

litigation is long drawn and expensive proposition 

let grand father file eviction proceedings against your father 

1) the said property absolute owner is your grand father, you or your siblings or your father cannot have rights to claim in self acquired property of your grand father. 

2)you can claim in ancestral property and also you can file partition suit in ancestral property,  without the consent of successor ancestral property cannot be sold or transfer. 

3) Incase if your grand father died without will then class 1 legal heirs i.e your father and your uncle are legal heirs Property will be divided equally in legal heirs. 

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See in case the proeprty is under ownership of grand father and further it is self acquired not ancestral as such you are having no right over it grand father can will , gift same in his life though if he demise without will gift or transfer then you have equal share otherwise only grand father can transfer same. Defence of possession also cannot be taken in case as such it is kind of permissive possession.

1. Thye property stands in the name of your grandfather and it is not an ancestral property as defined by law. It is the paternal property of your Uncle.

2. Collect evidence (specially medical prescription) tp prove that your grand father is not in a stable mental state for his aadvanced age.

3. So, if your Uncle produces any will or gift deed bequeathing or gifting the said property in the name of your said uncle, you can challenge the claim on the gropund that your grandfather, being not in a stable state of mond due to his advanced age, can not execute and register any valid lagal document as per law for which you being his legal heir after his demise will equally inherit his said property along with your Uncle. 

Don't sell it. He can't force to sell it.if he harrasses file Complaint under senior citizens Act and evict him.

1) Arrange family meeting and try to solve the problem be way of talk and tell them you're not leaving the house at any ground.

2) Don't give possession of house. One should talk to grandfather.

1. The property is the absolute property of your grandfather as the sale deed has been executed in his favour irrespective of who paid the registration fee.

2. During his lifetime your grandfather is at liberty to bequeath his property to anyone he desires. The true owner of property has the right to discriminate between his heirs at the time of making a bequest. 

Your uncle cannot ask you to leave the house

If at all anyone can do that is your grandfather who is the owner of the property 

A son cannot claim any ownership right in father's property so long as father is living 

A son only has a right of residence as a gratitious licensee and would be required to leave the house if the owner so desires

A son gets a right to his father's property only after the father's death, provided the property was not transferred during his lifetime or is willed by father to some other person 

Dear Sir,

You may claim adverse possession or settled possession.  You may file a suit for permanent injunction restraining them from interfering and alienating the property.  The proceedings may thus prolonged.  After the death of your grandfather both your father and your uncle get half share.

Hi,

In the present circumstances, you may file a suit for partition, declaration and injuction against your uncle and grand father. 

If this is  your grandfather's house, then your father cannot claim any rights over it for whatever reason, at least not during the lifetime of your grandfather.

Let your father drag on the issue for few more years to prolong the issue, by then your grandfather may not even survive, after which your father can claim his legitimate share as his legal heir/successors in interest.

For the present there is no point in agitating it since your father has no rights in the property legally.