I am thankful to all who had cared to give me their opinions on the subject. I have three facts, strong and substantial:
1. My brother is not ready to give any share to me (though he has only 2 daughters) and is very rich by himself
2. Now, I understand that he got the property transferred to his name through a properly registered gift deed from by father (as I have already conveyed, the property is my grandfather's and my father got it through a registered partition deed)
3. My father was not made to understand the facts (my brother made him believe that his daughter was to marry my son, which is not true - he broke the marriage proposal after getting the property transferred, which my father is not aware of even now)
Under these circumstances, is it possible to challenge the validity of the gift deed and claim for my right in the property.