Is what I intended—to donate fifty euros monthly from a financial grant for my autistic son—considered a vow that must be fulfilled? Is it permissible to reduce the amount donated if the grant's value is less than I expected? And is it permissible to give part of the charity to needy relatives of my husband?

First: If the wording of the vow or a formula indicating obligation, such as "It is a duty upon me for the sake of Allah to give charity," is not uttered, then this is not a vow, even with a firm intention. It is permissible to give the full amount as charity, or less, or not to give it at all. A vow depends on the wording that indicates commitment, or what stands in its place, such as writing with the intention of making a vow, or the sign of a mute person. Mere intention is not sufficient. Jurists have differed on whether a formula that lacks the word "vow," such as "It is a duty upon me for the sake of Allah to do such-and-such," obligates the one making the vow or not. Most of them hold that it obligates if it signifies commitment, while others hold that it is not valid unless the word "vow" is explicitly used.

Second: There is no harm in giving money to the husband's family, as this is a good way of maintaining ties. However, if they are self-sufficient with what their son sends them, then it is better to give the money to others to increase the beneficiaries and meet the needs of the needy.