Share in the property owned by Father

Sir, One of my friend from Mumbai has refereed me on to this site. My Name is Rahul M, and I am from Goa. My father has purchased a Land measuring 370 sq mtr for 4 Lakhs 20 years back. The market value of property today is 80 Lakhs. My father stays with me. I lost my mother 5 years back. I am married. I have a younger brother who is also married. Soon after marriage i purchased a flat and moved in. Since my brother was bachelor and wanted to settle on family front, I and my wife and my father gave him power of attorney to construct house and produce the same in the bank for availing loan. At that point of time he made verbal commitment that he would give my share to me .This happened in 2010-2011, since than he is not showing any positive sign of paying me my share of land. I am going thru very tough time hence i getting my share is very important. My question to you sir 1. Can he legally deny my share to me? 2. How much he is supposed to pay me? 3. How to address this issue mutually? 4. If there is no mutual agreement, how to approach legally.? 5. What roll my father has to play? 6. What property related documents i need to keep with me to produce as and when needed ? 7. Can i lawfully ask for copies of documents from the bank in which my brother has availed loan? if yes , what is the procedure? 8. From where other than bank can i get the property documents? Your reply to my above questions will help me in taking the matter further. Thanks and Regards Rahul M