بسم الله الرحمن الرحيم
(1) Yes, if your deceased father left behind one wife, one son and one daughter and none besides them i.e. the parents of the deceased person had already died, then all the property of the deceased person shall be divided into 24 shares, after paying due rights proceeding inheritance. Out of the total your mother shall get 3 shares, you shall get 14 shares while 7 shares shall go to your sister.
(2) Your mother should agree to divide the property of your father during her lifetime so that each heir could enjoy his share from today specially the married sister. May Allah give her taufiq. Amen
What do you mean by settlement? If you mean some land, property, house or cash which the company shall give to your father then it will also be included in the inheritance of the deceased person in the same way as the PF amount is the inheritance of the deceased person and all the heirs have their shares in the inheritance. Thus the amount of PF and settlement shall be divided among all the Shariah heirs of the deceased person according to Shariah, only your mother will not be its sole owner. The amount of PF and settlement has come in the account of your mother only because your father had declared her as his nominee).
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.