Is it permissible for the wife to give the Zakah (obligatory charity) of her money to her poor husband?
Yes, it is permissible for the wife to give from the Zakah of her money to her poor husband. And Allah Knows Best.
Can a person required to give kaffarah feed it to their own family members?
The kaffarah must be given to the poor and needy who are not financially dependent on the one giving the kaffarah.
If a person feeds it to their own family members, it does not count as kaffarah, and their obligation remains unfulfilled.
Is it obligatory to make up all missed prayers?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
Making up missed prayers (qaḍāʾ) is a sharʿī obligation, established by the practice of the Prophet ﷺ himself — when the disbelievers preoccupied him on the Day of the Trench and he missed the ʿAṣr prayer, he made it up afterward. This is further affirmed by the ḥadīth: "Fulfil what you owe to Allah, for Allah is most deserving of being fulfilled." (Reported by al-Bukhārī.)
Accordingly, a person who has missed prayers should set aside his voluntary and Sunnah prayers and replace them with make-up prayers in their stead. There is no objection to making up one missed prayer alongside each obligatory prayer that is performed — praying the equivalent missed prayer together with each current obligatory prayer as a practical and manageable way of gradually clearing one's debt of missed prayers. And Allah the Almighty knows best.
Is an elderly or chronically ill person required to pay additional fidyah if they delay it beyond the first year?
An elderly person or someone permanently unable to fast must pay fidyah by feeding one needy person for each missed day.
However, if they delay paying fidyah beyond the first year, no additional fidyah is required.
This differs from someone who delays making up missed Ramadan fasts (qada) without a valid excuse until the next Ramadan begins—such a person is required to pay an additional fidyah for the delay.