Inheritance

My father had died about 20 years ago. My sister has died recently. I am her only blood brother. Me and my sister shared same parents. My mother is still alive (Masha Allah). My mother re-married after my father's death and she has a son. I wanted to ask how my sisters wealth is to be distributed as I am incharge of it. In short, my sister died and has left behind:

1. A full brother.

2. A mother who has done second marriage.

3. A step brother (same mother different father).

Is my mother and step brother entitled to any of the property that my sister got from our father?