Is it permissible to give a needy father a sum from a vow designated for charity?

A vow contingent on the occurrence of something disliked (vowed to avert an undesired outcome) was prohibited by the Prophet (peace be upon him) when he said: "It does not bring about any good, and it is only extracted from the miserly." This means it is not a cause for good to happen, and the one who makes such a vow is condemned for miserliness. Some scholars, like Ibn Taymiyyah, considered it forbidden because it compels a person to an obligation when they are free from it, and the one who vows may regret it. Moreover, it implies a poor opinion of Allah, as if the vower does not trust that Allah will grant them unless there is a مقابل (exchange).

Regarding giving the vow to one's father: If a person has enough to support their father, then that is obligatory, and it is not permissible to give the vow to him, because his maintenance is obligatory. However, if the funds are insufficient for maintenance, then there is no harm in giving him the vow. It is permissible to give the vow to siblings if they are in need, as long as their maintenance is not obligatory.