Is it permissible for a divorced mother who has custody of her children to take a small portion of the child support paid by the father for her own expenses, given that she has no other source of income?

If the children's maintenance exceeds their needs, it is permissible for a needy mother to take from it. However, if the maintenance is sufficient, it is not permissible for the mother to take from it if it harms the children. The mother is entitled to a custody fee from the one obligated to provide for the child's maintenance. This fee should be taken from the child's own money; if the child has no money, then it is the responsibility of the one obligated to provide for their maintenance. The mother is not entitled to a custody fee if she is still married to the father or in her revocable waiting period (iddah) from him. However, a divorced woman, after the expiration of her iddah, is entitled to the fee.