If we have understood the question correctly, then we state that what has been given to your father’s second wife is a gift to her. This is her sole right.
If you want to ask her for a share, you may, remembering that she has a right to give you or refuse you. If this is not what you have asked, then rewrite to us stating your case clearly.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai