Estate Law Questions? Ask an Estate Lawyer.
Thank you for using JustAnswer. I am researching your issue and will respond shortly.
They're almost certainly totally separate. A trust can be "inter vivos" (set up during the life of the grantor to the trust) or "testamentary" (set up after the death of the individual). A trust CAN be set up as part of a will, but if your step mother set this up for your father, then the will would only dispose of what HE owns at the date of death.
A trust is a separate type of ownership. That is, he would not "own" the assets in the trust, and the terms of the preexisting trust will take precedence over the will. Only if the trust says that upon his death that the proceeds would be paid to his estate, would his will have anything to do with the distribution of the proceeds of that estate.
Hope that clears things up a bit. If you have any other questions, please let me know. If not, and you have not yet, please rate my answer AND press the "submit" button, if applicable. Please note that I don't get any credit for my answer unless and until you rate it a 3, 4, 5 (good or better). Thank you, XXXXX XXXXX luck to you!