Death of a sibling How to proceed without a will

You need to apply to become the adminisntrator of the estate.  This would require anyone else who has a right to serve as Administrator to renounce the right to serve - so if there are any other siblings for exmaples, or the decedent's children.  You will have to obtain a surety bond equal to the estimated value of the estate, adn you will have to file an Inheritance Tax Return.