It is very important to get a title deed for your property. Even if you try to sell the property it will be difficult to sell it without the title deed. Therefore it is advised that you must procure the title deed for the said property. Generally, if the original documents are lost, the practice is to register a FIR and post an advertisement and submit them to the Government authority to issue a new title deed.
You can apply before the Tahsildar for the Mutation Extract of the said property. The Mutation extract shows the inheritance certificate with details of previous owner, the present owner, the mode of acquisition of the property and the total extent of the property. As per the details the Mutation Extract will show that your mother as the last owner of the property. You can submit this Extract with your mother's death certificate to the Tehsildar. The death certificate will help you and your brother to establish their claim over the property and issue a fresh title deed from the Tehsildar after which you can apply for the Muatation again where you and your brothers will be registered as the owner. The title deed and the mutation extract will be enough for you and your brother to establish your ownership and sell the property subsequently.