My step father died before he could sign his will which was leaving 50% of his assets to me, according to the attorney he had hired. The attorney was in the process of submitting to the courts to have me as the executor/administrator of my dad's estate. Nearing the end a great-nephew called the attorney and said I was not blood related and therefore his grandmother (my dad's ill sister) should get the estate as next of kin. No one else in the family agrees with his actions.

Do I have any rights to fight this? This is the only father I have ever known and it is not fair for someone whom my father despised should think he is entitled. What can I do?

Have the attorney continue to probate the estate under the terms of the will. The lawyer will testify in probate court, that the will represents your father's wishes about the distribution of the estate. Most likely the court will accept the will and deny the distant relative's claims.

I get to disagree with Scott somewhat here.

Yes, you should go ahead with your attorney and fight this, The court may, with the testimony of the attorney accept this as the will. BUT. Since it was not signed, the other side can fight that, your father could have changed his mind prior to signing. No one knows his thoughts before death.

Legally a step child has no rights to inherit property, unless they were adopted, or listed in the will.

So it is not going to be a easy fight

What we don't know here is the circumstances of the will's creation and the father's death. I'm basing my answer on the assumption that the father died shortly and suddenly after drawing up the will. In that case, I believe the attorney's testimony will carry the day.

I'm not saying its going to be a slam dunk, if there was no will at all, you would be out of luck. But given the facts as presented and my assumptions, I think you have a good chance.