Boy refuses to marriage because of intercaste

Hi there, Me and my boyfriend are in love for past 7 years. we both are majors and job holders. 3 years ago he spoke to my parents about our marriage, and they were agreed, he asked 1 year time to convince his parents. Its been 3 years now, my parents forced him to marry me. His parents did not agree because I belongs to lower caste then theirs. In the month of June there were arguments went between our two families. Boy side have local political and police support so they tried to threaten my family. later again in the month of August boy went to my home town and said asked to make arrangements for the marriage. Now we all set to get marry in coming December 2015. 10 days later, boy brothers went to his workplace(Mumbai and spoke to him, from then on wards(1st of Oct 2015) he stopped talking to me and messaged me that he cannot go against to his parents. Later his brothers also came to my work place( Hyderabad) and warned me to leave him.His parents are emotionally blackmailing him that they will die if he marry me. Now he refuses to marry me. I don't know what to do. I cannot live without him. My parents does not know about this.. they are making arrangements for our marriage in my hometown. I don't know what happens if they come to know about this matter. I cannot live without him. Only because of his parents and their caste feeling causes all these things. How to convince him and his parents for our marriage. Please help me. Please guide me. Any guidance and support will be greatly appreciated. Please save two lives.