How can the father's house and garden be divided among the heirs, after the father relinquished the right of usufruct (airspace) to his elder and middle sons to build two additional floors at their own expense, and now wishes to relinquish the ground floor to his youngest son and two daughters, taking into account the value of the usufruct right used by the two sons, in order to achieve justice among all the children?

It is the father's right to gift his male and female children equally, and he is not permitted to favor some over others unless there is a legitimate reason. The preponderant opinion is the obligation to treat them justly, based on the Prophet's (peace be upon him) saying: "Indeed, your children have a right upon you to be treated justly."

Favoritism is permissible for a need of some children, such as illness, a large family, engagement in seeking knowledge, or due to the immorality of some of them, or if one of them uses what he receives for disobedience to Allah.

As for how to achieve justice, scholars have differed on the manner of equalization among children: Some said that justice means giving the male the equivalent of the share of two females, similar to inheritance. Others said that one should equalize between the male and the female. This latter opinion is the more apparent, based on the Prophet's (peace be upon him) saying: "Treat your children equally in giving, for if I were to prefer anyone, I would have preferred women."

In all cases, if there is no legitimate reason for favoritism, the father must fear Allah and treat his children justly.