What is the ruling if a postpartum woman becomes pure before forty days; are acts of worship obligatory upon her, and is she permissible for her husband?
If the postpartum woman becomes definitely pure before forty days, she must perform the ritual bath and perform acts of worship as a pure woman does. What was prohibited for her also becomes permissible, so she becomes permissible for her husband after her bath. The minimum duration for postpartum bleeding is a moment (an instant), and its usual maximum is forty days. Reaching forty days is not a condition; rather, it is sufficient for the blood to stop or to see the white discharge (qassa bayda'). And Allah the Almighty knows best.
Is the father a Mahram (Non-marriageable) to his son`s mother-in-law?
The father is a non-Mahram (Marriageable) to his son`s mother-in-law, so it is impermissible for them to look at each other, or to have a seclusion (Khalwah).
Is it permissible for someone who is unable to fast to pay the fidyah (ransom/compensation payment) to himself, due to his own poverty?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
It is not permissible, nor does it fulfill the obligation, for a sick person who is currently and permanently unable to fast to pay the fidyah (ransom/compensation payment) to himself, since it is a financial obligation owed by him, established as a standing debt upon him — much like any other debt he owes. If he were to pay it to himself, it would not thereby be discharged. So if he cannot find [anyone eligible to] pay it to, it remains a standing obligation upon him, and is not thereby waived. If Allah, the Mighty and Majestic, later grants him wealth, it becomes obligatory upon him to pay it out to the poor and needy.
Imam al-Khaṭīb ash-Shirbīnī (raḥimahullāh) said: "There is no difference in the obligation of the fidyah between the wealthy and the poor person; its benefit lies in its remaining established as a standing debt upon the poor person [until he is able to pay it] — and this is the more correct position (al-aṣaḥḥ), as indicated by the wording of ar-Rawḍah and its source text." [Mughnī al-Muḥtāj, Vol.2/P.174]
Accordingly: it is not permissible for a Muslim to pay the fidyah to himself while he remains poor. If the sick person is poor, he is not obligated to pay the fidyah immediately, and it remains a standing debt upon him until a time when he has sufficient means and wealth. And Allah, the Exalted, knows best.
What is the ruling of Islamic Law on the prayer of zawal?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
It is recommended (sunnah) to pray four rakʿāt — either with a single tasleem or as two separate sets of two rakʿāt — immediately following the sun's decline from its zenith (zawāl). This prayer is distinct from the regular Sunnah prayer of Ẓuhr (sunnat al-ẓuhr al-rātibah), as explicitly stated by the Shāfiʿī jurists.
It is mentioned in Nihāyat al-Muḥtāj: "The prayer of zawāl is offered after the sun's decline — so were one to perform it before that, it would not count. It consists of two or four rakʿāt and is distinct from the Sunnah of Ẓuhr, as is evident from the fact that it is mentioned separately after the regular Sunnah prayers, and it becomes a make-up prayer (qaḍāʾ) if a long period of time passes by customary reckoning... Al-ʿAlqamī stated: 'Scholars refer to this as the Sunnah of Zawāl, and it is distinct from the four rakʿāt that constitute the Sunnah of Ẓuhr.' Our shaykh said: Al-Ḥāfiẓ al-ʿIrāqī stated that among those who explicitly affirmed its recommendation was al-Ghazālī in al-Iḥyāʾ, in the chapter on devotional litanies, noting that there is no tasleem between them — meaning there is no break between each pair of rakʿāt."
The time of the sun's decline (zawāl) marks the very beginning of the time for the Ẓuhr prayer.
And Allah the Almighty knows best.
