If siblings have the same mother but different father, can they inherit from each other?

Much more information is needed here but it is a great question since you are coming from Louisiana, because it matters there. If a person dies with a Will then there is no issue here if they name their siblings (half or whole) as inheriting in that document.  But if they die intestate - with out a Will - then the intestacy statute will govern and in Louisiana half siblings will indeed inherit differently. In this case the deceased person’s separate property is divided equally between his or her mother’s and father’s family lines. The mother’s family line gets one-half of the property and the father’s family line gets the remaining half.  Any brothers and sisters with the same parents will inherit through both sides of the family lines. But the half-brothers and half-sisters will only inherit through the mother’s or father’s line, as the case may be. So as you see descendants of deceased half-siblings do not inherit the share that their parent would have inherited.  The children of a deceased half-brother would not inherit in the same manner as a full-blood sibling. Seek legal help here.  Good luck.