With such an extensive estate, I'm assuming that your father had a Will. And the fact is that a parent may disinherit a child. Typically, so to prevent a later claim that a child was inadvertently omitted from a Will, a token sum is left to the child in question. This is most likely why you inherited the $500. Accordingly, unless you can prove that your fatherr was mentally incapacited at the time that he made his Will, was under undue influence to disinherit you (which you essentially were) or the like, you cannot contest its validity. That having been said, in the unlikley event that your father died "intestate", that is without a Will, then as his child you would be your father's heir, in which case you would have inheritance rights.