If a woman dies and leaves behind full siblings or half siblings through the mother
Question

                My sister died, she was not married, and our parents have passed away before she died. We are 3 sister and 3 brothers, who were the heirs of her property, We distributed her wealth among 6 of us, the brothers got 2 shares and sisters got one, Recently my brother sold a piece of land and said that my sister (who died) also had a share in it so he distributed her share again in the same manner. This is what we knew about the inheritance, But I read in surah Anisa about the inheritance of ‘Kalaala’ and according to my understanding of the verse # 12 only one third should have been distributed. Now my question is, if what we did was not correct what we should do, I am realy worried as I was managing her things. Other siblings are not concerned, and also it has been more than 4 years that we distributed the wealth. I will be very grateful please advice me.
Praise be to Allah.
    If you are full siblings of the deceased or siblings through 
    the father only, then the division of the estate that was done is correct 
    and there is nothing wrong with it. 

    But if you are siblings through the mother only, then there 
    is the issue of kalaalah, which may be explained as follows: 

    1.If a person dies and leaves 
    behind full siblings, then the estate is to be divided among them with each 
    male getting the share of two females. There is consensus among the scholars 
    on this.

    Ibn ‘Abd al-Barr (may Allah have mercy on him) said: With 
    regard to the words of Allah at the end of Soorat al-Nisa’ (interpretation 
    of the meaning): “if there are brothers and 
    sisters, the male will have twice the share of the female” [al-Nisa’ 
    4:176], there is no difference of opinion among the earlier and later 
    Muslim scholars that inheritance of siblings through the mother only is not 
    like this. Therefore they are unanimously agreed that the siblings mentioned 
    in this verse are siblings of the deceased through the father and mother 
    (i.e., full siblings) or through the father only.

    End quote from al-Tamheed, 5/200. See also 
    al-Mughni, 6/162 

    2.If a person dies and has no 
    father or child, and he leaves siblings through the mother, this is a case 
    of kalaalah. If there is only one brother through the mother, he gets one 
    sixth. If there are more than one, they get one third, which is divided 
    equally between males and females. This is one of the cases in which the 
    share of the female is like that of the male.

    If we assume that you are siblings of the deceased through 
    the mother only – and you are not full siblings – then you take one third of 
    the estate and divide it among you equally. If she had no other heir, then 
    the rest of the estate comes to you, so the estate comes to you through 
    allocated shares and by default, and it is to be shared equally among you. 

    And Allah knows best.