The will for an heir is invalid
18-3-2009 | IslamWeb
Question:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) is His slave and Messenger. My father in his life time has,divided his property of 12 flats,of 540sq feet each,and an amount of Rs.80,00000/-(80 lakhs) has followers.He has 3 sons and 3 daughters,1 son he has given 2 flats no cash,2 son 4 flats no cash,third son 2 flats,no cash,3 daughters 4 flats and 80 lakes. my sisters are unmarried,we have requested our father that this is against that law of Allah,but he says who will take care of my daughters after me,I have already said to him the One who has made the law will take care of his slaves,it is indeed him who take care of his slaves.he has already made arrangement that my sisters get 15 to 20 thousand per month,before dividing his property.My sisters has received the cash amount, and unfortunately one of my sister has died in her bank account she has amount of 30 lakes and 2 flats are in her name,my other two sister's are having asses to her bank account are are withdrawing money by debit cart at will,and my father is give his consent to this.I want to know whether they will be held is front of Allah on the day of rescission,my brother's are very angry with my father for the injustice upon us,but I fear Allah,and love Allah and His slave and Messenger so I have given up all my right if any,and Allah is witness to it,if my father has committed error in the eyes of Allah and he he will be caught by Allah for his deeds.
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
According to the most preponderant opinion of the jurists 
a parent is obliged to be just when gifting his/her children as Allaah Says (what means): {Indeed, Allaah orders justice and good conduct.}[Quran 16:90] Also, the Prophet said: "Fear Allaah and be just between your children (when gifting them)…" Since you mentioned that your father gifted two flats to one of his sons, and another two flats to another son, while he had gifted four flats to a third son, then this is not the justice that Allaah and His Prophet ordered. Moreover, if the total money that he had given to a daughter is more than what a male had received, then this is an injustice as well.
Therefore, your father should fear Allaah because discriminating between the children when gifting them inherits hatred and causes rancor. He should be just between his children about what he had gifted them either by giving more to whomever he did not give enough, or to take back from those to whom he had given more than what they deserved. This is in regard to the gifts which he had given to his children and they already possessed it. As regards what he wants his children to take after his death, then this is a religiously void will because it is a will for an heir and it is invalid unless the remaining heirs agree to it.
With regard to the sister that you mentioned that she died and left an amount of money in her account, then if this money is really possessed by her, then it is transferred to her heirs after her death. Her two sisters has no right to take from it because they are not her heirs, even if this sister has no heir other than her father, then the existence of the father prevents them (her sisters) from inheriting from her. The permission of the father to her two sisters to take her money without giving permission to the other brothers is also an injustice in gifting them.
For more benefit, please refer to Fataawa 90159 and 96941.
Allaah Knows best.