Is it permissible to include unpubertized siblings in expenses shared from the agreed-upon salary, or is it permissible to take what is insufficient as a debt?

The guardianship of minors belongs to their father. If he is absent, then to their inheritors from among their relatives, and then to the judge. A brother does not have guardianship unless appointed. It is permissible for whoever has guardianship over his young siblings or manages their affairs to mix his food with theirs and to consume from their wealth in a reasonable manner when needed, as stated in the noble verse: "And whoever is rich, let him abstain [from taking a fee]; and whoever is poor, let him eat in a reasonable manner." Their wealth must be preserved, and nothing should be taken from it except what is needed for their maintenance in a reasonable manner. It is permissible to borrow from it in a reasonable manner, provided it is documented.