1. It appears that your father has availed loan from a Bank duly mortgaging his said 2000 sq.ft house.
2. So, a charge has been created on the said Bank and a security interest has been created on it against the said loan availed by your father.
3. if your father fails to repay the loan and his loan account becomes Non Performing Asset (NPA), the the lending Bank will initiate SARFAESI proceeding against your father and take physical possession of the said mortgaged property to sell it off for recovering its dues.
4. As per law, the mortgaged property can not e dealt with by the mortgagor being your father herein for which there can not be any transfer of ownership of the said mortgaged property without releasing the mortgage on it by paying off the dues of the said Bank.
5. Ask your brother to pay off his dues or settle the loan by making one time settlement with the Bank against the loan he has availed in the name of your father.