Is it permissible to give charity with the intention of earning reward for one's parents if the mother refuses the money because her demand for the wife's divorce was not met, and is not divorcing the wife considered disobedience to the mother?

It is not obligatory to obey the mother if she requests the divorce of the wife merely due to disagreements between the two families, and divorcing the wife is not an act of honoring the mother. One must honor the mother to the best of their ability, strive to please her, and obey her in what is good and permissible. Giving charity on behalf of the father is undoubtedly valid. As for giving charity on behalf of a living mother, there is a difference of opinion among scholars regarding the validity of gifting the reward (of such an act).