What should a woman do who vowed to donate half of her salary as charity, but then her expenses and debts increased? Is it permissible for her to give [money] to her father from the other half?

A vow must be fulfilled, as Allah the Almighty says: "And among them are those who made a covenant with Allah, [saying], 'If He should give us from His bounty, we will surely spend in charity, and we will surely be among the righteous.' But when He gave them from His bounty, they withheld it and turned away, while they were refusing. So He penalized them with hypocrisy in their hearts until the Day they will meet Him - because they broke what they promised Allah and because they used to lie." Repaying a debt takes precedence over fulfilling a vow if the debt predates the vow, and it can be repaid from the other half if the first half is insufficient. However, if the debt is incurred after the vow, it does not take precedence, for fear of deception. If the vow is for general charitable causes and the father asks for money, there is no harm in giving him from it, as it is considered a good cause.