Father cheating on the sons money.

Hello, In 2008 , my father resigned from his job at 56 years and got 9 lakhs as PF and other benefits. He also has a site bought in his name. I completed education & got job in 2008 and was asked take care of them. Trusting my father, i kept sending him money for 6 years assuming my father will rationally spend and do the savings in my name. Since they had no home, i also invested in a home in bangalore taking loan. In total, i sent them 75lakhs (includes house downpayment of 20lakhs). But unfortunately, my parents started spending luxuriously and spent all my money. When i asked my father to give me my money back, he is saying it is all spent. He used that money for trips, his old site loan, my sister marriage loan and home expenses. He is now having the 18 lakhs fixed deposit which has my savings also but he has put in his name and he is not willing it pay back. Also he is saying he will sell the site and use it for their lavish spending. Please advise how can i get my money back. If not all atleast i need to claim a part of my savings. I am ready to take care of their food and health but cannot afford to lose all my savings. I kept sending money for 6 years thinking the site and the Fixed Deposit (18lakhs) will be passed on later to me. I have bank statments to prove that the money was sent by me and he owes me since all he got was 9 lakhs during resignation but they have spent more than 50 lakhs. They are also blackmailing me that they will commit suicide if i ask my money back. Please advise.