Praise be to Allaah.
The parents have to treat their children fairly when giving
gifts, because of the report narrated by al-Bukhaari (2586) and Muslim
(1623) from al-Nu’maan ibn Basheer (may Allaah be pleased with him) who said
that his father brought him to the Messenger of Allaah (blessings and peace
of Allaah be upon him) and said: I have given this son of mine a slave that
belonged to me. The Messenger of Allaah (blessings and peace of Allaah be
upon him) said: “Have you given a similar gift to all your children?” He
said: No. The Messenger of Allaah (blessings and peace of Allaah be upon
him) said: “Then take it back.”
According to a report narrated by al-Bukhaari (2587) [the
Prophet (blessings and peace of Allaah be upon him) said: “Fear Allaah and
treat your children fairly.” He said: So he went back and took back his
gift. According to a report narrated by Muslim (1623): The Messenger of
Allaah blessings and peace of Allaah be upon him said: “O Basheer, do you
have any other children?” He said: Yes. He said: “Have you given to all of
them like you have given to this one?” He said: No. He said: “Then do not
ask me to bear witness for I will not bear witness to injustice.”
There is no differentiation between the mother and the father
in that regard. See the answer to question number
67652. So it is haraam for her
to differentiate between her sons and daughters, except with the consent of
all.
It is important to know the difference between maintenance
and gifts. Maintenance is according to need. For the one who needs to get
married for example, the father should spend on his marriage, but he does
not have to leave behind money for those who are not married; rather it is
not permissible for him to do that, because this will come under the heading
of gifts and not under the heading of maintenance that the son needs.
Based on that, if you are going to get married and you need
some money, then your mother may give you what you need, and she is not
obliged to give to the rest of your siblings the same as she gave to you,
and she does not have to ask their permission.
With regard to your other sister, your mother should not give
her something until she is going to get married and needs the money, at
which time she may give her what she needs and no more than that.
See also the
answer to question number 119655.
And Allaah knows best.