Notarized Agreement

It is an agreement , it can be considered.  If your brother denied your share, you will have to file a suit for partition and seperate possesion of your share.  Burden lies on to prove that property is purchased jointly.
 

In my opinion such a family arrangement requires registration.

The agreement is no doubt a genuine document and you can rely on the agreement to have your share in the property. A civil court will have all the jurisdiction to try the suit. There are a lot of proofs that will go against your brother.

 transfer of property Act govern the transfer of propery in India. When there is specific act the contract act doesn't override the Transfer of property act

the agreement is legal and you can file suit of performance of contract an in sec 49 of the Regi. Act no corresponding ammendment.

Notarised family agreement does not have legal sanctity. it needs to be registered if the property is divided through such instrument.

The agreement is like a family settlement. since the registry is in the name of your brother therefore you do not have any title over the property. on the basis of such document you may file a partition suit. you can rely upon the signed document. hoever admissibility of the agreement depends upon the court because unregistered document related to the property may not be admissible as eveidence under evidence act. filing partition suit is the one option for you.