How can a father achieve justice among his children, and should he allocate to the younger ones a grant sufficient for their marriage and education, equivalent to what he spent on the older ones during his lifetime?

The preponderant opinion is that it is obligatory to be just among children in gifts and endowments, unless there is a special need that necessitates preference. As for expenditures, equality is not obligatory; rather, the father spends on each of them according to their needs. Thus, it is just for him to cover the educational and marriage expenses of the younger children, just as he did for the older ones. Ibn 'Uthaymeen mentioned that justice in expenditure means giving to each needy person what they need, without giving the same to another if they do not need it, such as someone who needs expenses for education or marriage or similar matters. He also stated that a bequest to marry off someone who has not reached the age of marriage from one-third of the estate is not permissible.