1. If the property was registered in the name of your mother, upon her demise in the absence of any WILL left by her, her property will devolve by way of inheritence upon her legal heirs. The legal heirs are you and your brother in the instant case.
2. To get the property in your names, one has to first apply for and get Legal Heir Certificate from the Tehasildar of the area concerned.
3. On the strength of the Legal Certiicate, the mutation of the names has to be got done in the Municipal Records.
4. Your brother has to execute a Relinquishment Deed, relinquishing his right, title and interest in the property in your favour, and that Relinquishment Deed needs to be compulsorily Registered with the Sub-Registrar's office. THEN AND THEN ONLY THE relinquishment Deed is valid, otherwise not.
5. Now, on the strength of the Legal heir certificate, and the copy of the Relinquishment Deed, you can get the property mutated in your name in the Municipal Records.
6. Once your name gets mutated in Municipal Records, the Tax Demand will come in your name and you will be able to pay the property tax.