A question about inheritance
Question

                A girl who was not married died, and her parents are separated. Who inherits from her and how is her estate to be divided? 

One of her parents has died, and she has no full brothers or sisters; she has two sisters and two brothers from her mother, and she has six brothers from her father. Who inherits from her and how much is the share of each of them?.
Praise be to Allah.
    This is one of the issues of inheritance and may be 
    understood in the following ways: 

    1.

    If she died and left behind a father, a mother, siblings 
    through the mother and siblings through the father,

    in that case her father and mother only inherit from her. The 
    mother gets one-sixth and the father gets the rest. 

    Ibn Qudaamah (may Allaah have mercy on him) said:

    if there are two parents and two brothers or two sisters, 
    then the mother gets one-sixth and the rest goes to the father. End quote.
    Al-Mughni (6/258). 

    2.

    If she died and left behind a father and siblings through her 
    mother and siblings through her father,

    in that case only her father inherits from her and her 
    siblings do not take anything, because the father prevents other siblings 
    from inheriting and they do not inherit anything along with him. 

    Imam al-Shaafa’i (may Allaah have mercy on him) said:

    Neither the brothers nor the sisters -- whoever they are -- 
    inherit anything along with the father. End quote. Al-Umm (8/239). 

    3.

    If she died and left behind a mother and siblings through the 
    mother and siblings through the father 

    In that case the mother inherits one-sixth, because Allaah 
    says (interpretation of the meaning): “if the 
    deceased left brothers or (sisters), the mother has a sixth” [al-Nisa’ 4:11]. 

    The siblings through the mother inherit one third, which they 
    share and the share of the male is the same as the share of the female, 
    because Allaah says (interpretation of the meaning):

    “If the man or woman whose inheritance is in question has 
    left neither ascendants nor descendants, but has left a brother or a sister, 
    each one of the two gets a sixth; but if more than two, they share in a 
    third” [al-Nisa’ 4:12].

    What is meant by brother or sister in this verse is the 
    brother or sister through the mother, according to scholarly consensus. 

    The siblings through the father take the rest by default . 

    And Allaah knows best.