I looked up the law of succession in Louisiana. Normally everything would first go to the surviving spouse, but since your grandfather is also dead, here is the order of heirs who would "take" when there is no will:
1. Descendants.
2. Parents.
3. Siblings.
4. Siblings' descendants.
5. Ascendants, starting with decedent's grandparents, in the nearest degree of kinship to the decedent.
6. Collateral relatives, in the nearest degree of kinship to the decedent.
You can read more about it here:
http://www.finance.cch.com/pops/c50s10d190_LA.asp