Mutation of property

In my understanding, there could be no harm, if the beneficiary is in possession. To my knowledge, the Municipal authority cannot keep the matter pending unless the Will is, ex facie, invalid. It is for the other party, who disputes the Will, to approach the Court and seek remedy.

Probation of will is not compulsory in Rajasthan if it is not objected. 

In your case your brother has raised the objection in getting the property mutated in your name (as beneficiary of will) it shall not be sanctioned in your favour.

Now you have the only option to get the will probated by District Civil Judge where property is located.