On grand father demise land would devolve on your grand mother , father and his siblings 

legal heirs are at liberty to sell the land if there are no restrictions imposed on sale in terms of allotment by govt 

An order is issued by State Government  G.O.Ms. Dated: [deleted] permitting sell of  land assigned to freedom fighters by Government. With the help of that order you can sell the land. Land can be sold by all legal heirs together or any one legal heir to the extent of his share in land.

You have no share in property during your father lifetime 

on father demise intestate you would inherit his share in land along with other legal heirs 

Your father along with his siblings shall be the legal heirs to succeed to the estates of his deceased father.

You do not have any rights in the property during the lifetime of your father. 

If the conditions of allotment of this property do not prevent the legal heirs from selling or alienating the property then your father after consulting with his siblings,  can decide about further course of legal action on this. 

No.

Neither you nor anyone else shall be entitled for any share in the property as a right during the lifetime of your respective fathers. 

- As per Madras High Court , Government cannot acquired the freedom fighters land from his family after his death . 

- Hence, after the death of grandfather , his property would be devolved upon all the legal heirs , and they can sell the property .

- If your father is only claimant i.e. no other legal heirs , then he having his right to sell the same , and during his life time you have no right over that property. 

Dear Sir/ Madam

In case of freedom fighters, the government allots land but the recipients cannot sell it for 12 years from the date of allotment. After the completion of the tenure, the land can be sold to whosoever.