What is the ruling on someone who prays but does not fast, without a valid excuse?
Fasting is one of the pillars of Islam, and a Muslim's faith is incomplete if they neglect the obligation of fasting while being physically capable of observing it.
Can someone who begins a voluntary fast break it?
It is preferable for someone who begins an act of worship not to break it.
Allah the Exalted has said {what means}: "and let not your [good] deeds come to nought!" [Muhammad/33].
However, if a person starts a voluntary fast (nafl) and needs to break it, they are going against what is preferable, but there is no sin upon them.
What should a person who doubted having missed a pillar of prayer do?
All praise be to Allah, The Lord of The Worlds. The prayer of one who doubts having missed one of its pillars is valid, and nothing is due on him/her since having a doubt after offering the act of worship doesn`t undermine its validity. And Allah Knows Best.
Who is required to give fidyah for fasting?
Fidyah—feeding one needy person for each missed fasting day—is required for:
1. Those who are permanently unable to fast, such as:
○ Elderly men and women who are too weak to fast.
○ People with chronic illnesses that have no hope of recovery.
2. Pregnant or breastfeeding women who break their fast out of fear for their child (fetus or infant).
3. A person who delays making up Ramadan fasts (qada) until the next Ramadan begins, without a valid excuse.
4. The estate of a deceased person who had missed obligatory fasts and had the ability to make them up but did not do so.