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, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
What that father has done of giving a gift to his sons and denying his daughter is an injustice in gift-giving which is not permissible. It was obligatory upon him to treat his sons and daughters fairly when it comes to gift-giving.
However, as long as that father passed away, then that gift is valid and takes effect by his death and cannot be annulled unless the two sons seek to achieve justice in that gift and that would indeed be a good thing. Zaad Al-Mustaqni‘ (a Hanbali book) reads: “It is obligatory to treat children justly in gift-giving according to their shares of inheritance. However, if some of them are given more or less, then the parent has to fulfill justice either by annulling the gift or by increasing the share of those who were given less than their fair share, but if he/she died before doing that, then it (that gift) takes effect.” [End quote]
As for the two sons who denied that daughter the right to inherit from her father, then they have no right to do that; rather, her share is confirmed by the Book of Allaah The Almighty and no one has the right to deny her that right.
Finally, please take note that the big house which that man registered in his wife's name should be reconsidered. If she had owned and possessed it from him before his death, then it is a valid gift that should be fulfilled. But if she did not possess it before his death and he only registered it in her name so that she would take it after his death, then it is an invalid will unless all the heirs agree to it willingly.
Allaah Knows best.