You are not having any rights in your grandfather's property especially during the lifetime of your father.

Your father is the right person to take any action on this or to ignore the matter.

Moreover, it is your uncle's decision to ask for a huge and unreasonable price for selling his share in the proeprty, he cannot be forced even by filing a suit or by any procedures of law.

Hence no legal action can be maintainable even if your father wants to file one.

Only if your father authorise you through POA to file partition suit on his behalf.

And without registered release deed in fovor of brothers, sister still have 1/4th share in property.

1. See in life of dad he is absolute owner of his share if he is not willing to file a suit of partition for same you cannot file it , your right is not created.

In case your father gift his share to you , you may file a suit for partition in his life.

If it's from your father side and a ancestral property then you can file suit. 

Your father can file suit for partition for division of property by metes and bounds 

2) you have no share in property during your father lifetime 

1. During the lifetime of your father you have no share in the property of your grandparents which devolved on their children through intestate succession.

2. Only your father can file a suit for partition to cull out his share in the property.

Dear Sir,

You are suggested to first serve a legal notice to uncle asking your reasonable share and if denied, you may file the suit of partition as well. It will be better that you take power of attorney for proceeding the matter in his behalf. Else, also you may proceed, but you may claim only your share.  

Yes you can go ahead

1. IF property belonged  to Grand Parents, THEN you (son) will be classified as Class-II legal heir and not eligible to file for Partition Suit, till your Father is alive.

2. Partition Suit can be filed ONLY by Children of Grand Parents.

Not at this stage. You can claim  your share only when your father is expired (god forbid) as his legal heir.

Either enter into family settlement deed with your uncle or take the money being offered to your father or convince your father to file a suit.

Yes you may file a partition suit as you too have a share in the property.

Make all the shareholders a party to the suit.

No, you cannot file suit for partition during life time of your  father.

However, your father has to issue notice for partition to his brother and if refused by him, he has to file suit for partition.

Your father can authorize you to file and prosecute the partition suit on his behalf, but he has to give evidence.

During life time of your  father, you have no share or right in the property.

Yes you can file suit for partition of property but it will be better if your father files suit to get his share from properties of his parents. 

- As per law, after the death of your grandparents , who died without leaving any WILL, the property would be devolved upon their legal heirs. i.e  1 daughter and 3 sons,

- Since, daughter has released her share , hence the property will be distributed between your dad & uncle, equally , because she has not left her share in favour of either of two claimant. 

- Legally, during the life time of your father , you have no right to claim any share over the property. 

- However, if your father not willing to take legal action , then you can file partition suit on his behalf , and not directly. 

if said property is ancestral then you can file partition suit.