Is the money requested for financial aid considered a mandatory expenditure for the father, and is he blameworthy if he does not pay the amount due to not possessing it, and is it permissible for the mother to ask him to borrow money to pay it?

Financial support is a right of the wife over the husband in exchange for her enabling him to himself. If she leaves the house without his permission, she forfeits her right to financial support, because she has disobeyed and relinquished the husband's right. She must repent and return to her husband's house or seek his permission. The husband is not obligated to send the amount she requested, but he may do so as an act of kindness.