Is it permissible to stop fasting a yearly month that was vowed for the recovery of a son who is still ill, especially given the difficult health, social, and financial circumstances that have befallen the one who made the vow?

Vowing is disliked, even though fulfilling it is obligatory, because the Prophet, peace and blessings be upon him, said: "It does not avert anything; it merely extracts from the miser." A vow of obedience and righteousness must be fulfilled according to the intention of the one who made it. If the vow was contingent upon the complete recovery of the son, then it is not obligatory to fulfill it except with that. But if it was contingent upon the improvement of his condition, then it has become obligatory to fulfill it. If you are unable to fulfill the vow, then you must pay the expiation for an oath, as the Prophet, peace and blessings be upon him, said: "The expiation for a vow is the expiation for an oath," which is: freeing a slave, or feeding ten poor people, or clothing them. If one cannot find [any of these], then he should fast for three days.