1. IF Father demised without executing any Will or Nomination, relating to his interests in the Company and Partnership Firm, THEN you are entitled to equal share in the Fathers interests, in in the Company and Partnership Firm.
2. File Civil Suit for the same, BUT supported with some basic documentary evidences (balance sheets, bank statements, income tax returns, ROC records, incorporation documents like AOA, MOA, etc....). IT is a very long period, BUT still would be worth a try and brothers may come down for settlement.
Keep Smiling .... Hemant Agarwal