1) you don't have clear and marketable title to the property
2) you ought to have purchased said property by regd sale deed
3) will can be revoked by seller any time and power of attorney ceases on death of seller unless coupled with consideration
4) is seller still alive ? Ask him to execute sale deed in your favour and revoke POA granted to your brother
5) In the alternative ask your brother to execute sale deed in your favour
5) I do hope POA is registered as for sale of property POA now needs registration
6) settle with your brother if possible