Legal Question in Wills and Trusts in Pennsylvania

No. You have no rights of inheritance from your stepfather unless your stepfather either adopted you or unless he made a will naming you as a beneficiary or named you on a beneficiary-designated asset (like an IRA or life insurance policy or a beneficiary on a payable on death account).

When your mother died, did she have a will? If not, what assets did she own and how were these titled? You would have been entitled to inherit 50% of any probate assets from your mother at the time of her death if she had no will and lived in PA. However, not all assets are probate assets. Things like life insurance, IRAs, joint checking accounts or land owned as a joint tenancy with right of survivorship or tenancy by the entireties (which is only available to husbands and wives) all pass outside probate. So it is possible that if your mother and her husband had a lot of non-probate assets, that much of it would have passed to your step-father.

You do not indicate if your step-father had a will or what he owned or if you were adopted. Did your step-father formally adopt you? If so, then for inheritance purposes you would be treated as if you were your step-father's biological child. If not, did your step-father have a will? If he did then he would have to name you as a beneficiary. If not, then you have no right to the funds and you are not the closest living relative to your step-father as you are not related to him at all.