Who must pay children's expenses
If a father is on pension and has a child undergoing his studies, who should bear the latter's expenses — the father or his eldest son who was exempted from military service and is the family's breadwinner? Is the father obligated to bear the expenses of his adult daughter who cannot find work?
There is a scholarly consensus on a father's obligation to bear his children's expenses due to the words of Allah the Almighty Who says,
… and clothing and maintenance must be borne by the father in a fair manner. [Al-Baqarah, 233]
Since Allah obligates a father to provide for his child's mother on account of her child, then it is with greater reason for him to support his child due to the words of the Prophet to Hind, Abu Sufyan's wife, when he told her, "Take what suffices you and your children with fairness" [reported by Bukhari and others through 'A`isha (may Allah be pleased with her)]. Had not a child been entitled to paternal support, the Prophet would not have permitted Hind to take from her husband's money; this is because a Muslim's property is sacred.
A father must be either financially capable of supporting his child or able to earn in excess of his own expenses. A father's obligation to support his child is not waived except if he is incapable of earning a livelihood such that he is financially dependent on any of his ancestors or descendents. In such a case, the obligation to support his child is waived and he is considered nonexistent since it is not feasible to require him to provide for others when he himself receives financial aid. This is the opinion of scholars concerning paternal support which rests solely with the father. Because a child is attributed to its father and is a part of him, the obligation of child support is not waived except on account of his financial disability.
Who must support the child if the father is financially compromised?
If the father is financially compromised and does not earn a living, the obligation rests with those who are obliged to support the child had the father been absent; these include the grandfather, brother, paternal uncle and their children. The expenses are considered a debt upon the father who must pay it back whenever he is able to.
Children are entitled to paternal expenses if they are financially compromised and do not have money or any income. A father is not obliged to support a child who has the means to support himself. However, in contemporary societies, a student is unable to earn his living on account of his studies which will qualify him in the future to earn a living.
The opinion implemented for fatwa and by courts
Financial support is incumbent upon relatives to whom marriage is forbidden other than ancestors or descendants. These include brothers and sisters and their children, and maternal and paternal uncles and aunts. This is based on the words of Allah the Almighty Who says,The same duty is incumbent upon the father's heir. [Al-Baqarah: 233].In Ibn Mas'ud's non-canonical (Ar. shadh) Qur`anic recitation, the verse reads as, "The same duty is incumbent upon a father's non-marriageable heirs." This is the opinion of Hanafi scholars whose condition for this obligation is affluence and not merely the ability to earn a living. This is because financial support of relatives is by way of maintaining ties of kinship — it is not obligatory except for an affluent relative.
It is also a condition that financial support of relatives be established by a judicial verdict. The book Bada`i Al-Sana`i mentions that supporting other than one's children is not obligatory without a judicial verdict and therefore requires filing a lawsuit.