Are we entitled to demand that our paternal uncle's wife and his children continue to pay the usual amount, despite the deterioration of my uncle's health and their reduction of the amount paid?

If a father saves money for his sons to help them marry, it is a good deed. However, if he does not do so, he is not to be blamed, as it is not obligatory for him. It is obligatory for the sons to honor and revere him. It is not obligatory for the uncle's wife or his sons to give the father what the uncle used to give him, because the uncle has become severely ill, and in such a state, his gifts and his agency are invalid due to his loss of legal capacity. Al-Kharashi stated in "Sharh Mukhtasar Khalil" that it is obligatory to place a person under interdiction if he suffers from a severe illness from which death is common. Similarly, Al-Kasani stated in "Bada'i' al-Sana'i'" that among the nullifiers of agency are the incapacity of the principal and his interdiction. Ibn Qudamah mentioned in "Al-Mughni" that the disqualification of one of the parties from being legally capable of acting, such as being interdicted for foolishness, is like death, because he no longer possesses the ability to act.

Therefore, the uncle's authorization to his wife or sons to disburse a monthly salary to the father is nullified due to the severe illness that caused him to lose his legal capacity. Hence, they are not obligated to implement what he authorized them to do or what he enjoined upon them as long as he is alive, because the agency is nullified by the illness. However, if the uncle dies, the sons can demand their right to the bequest, because what emanated from him is considered a bequest that is to be disbursed from one-third of his wealth.