Is it permissible for a person to give the Zakah (obligatory charity) to his daughter-in-law?
Yes, it is permissible for a person to give the Zakah to his daughter-in-law if she was poor, and none provided for particularly by whom are obliged to provide for her. And Allah Knows Best.
What is the ruling on fasting only on Friday, Saturday, or Sunday?
In voluntary fasting (nafl), it is disliked (makruh) to fast only on Friday, Saturday, or Sunday.
However:
● If one fasts a day before or after Friday, then that is permissible.
● The same applies to Saturday and Sunday—fasting them along with another day removes the dislike.
● Fasting all three days (Friday, Saturday, and Sunday) together is not disliked.
If any of these days coincide with a recommended fasting day, such as Arafah or Ashura, then fasting it alone is not disliked.
Is it permissible for one who sacrifices on behalf of another, with the latter's permission, to eat from the sacrifice?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
It is permissible for one who sacrifices on behalf of another with his permission to eat from the sacrifice with his permission, and he takes his place in distributing its meat.
It is stated in Hashiyat al-Jamal 'ala Sharh al-Minhaj (Vol.5/P.262): 'If a person sacrifices on behalf of a living individual with his permission, does he take the place of that individual in distributing the meat, because permission for the sacrifice implies permission for distribution, or does it depend on explicit permission? There is room for consideration, but the former view is not far-fetched.' And Allah Almighty knows best."
What is the ruling on someone who curses the religion or commits an act of disbelief during the day in Ramadan?
Whoever apostatizes (leaves Islam) while fasting, their fast is invalid. Cursing the religion is an act of apostasy (may Allah protect us from it). Such a person must return to Islam by pronouncing the Shahadah (testimony of faith), seek Allah’s forgiveness, refrain from eating and drinking for the rest of the day, and make up for that day’s fast later.