What is the ruling on reciting aloud (*jahr*) in a silent (*sirriyyah*) prayer?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Reciting aloud (jahr) in the Fajr prayer, in the first two rakʿahs of Maghrib and ʿIshāʾ, and reciting silently (isrār) in the Dhuhr and ʿAṣr prayers is a sunnah. If the worshipper recites aloud where silence is prescribed, or the reverse, his prayer is valid, although it is better to follow the sunnah, in imitation of the Prophet (peace and blessings be upon him). Abū Hurayrah (may Allah be pleased with him) said: “In every prayer there is recitation. What the Messenger of Allah (peace and blessings be upon him) let us hear, we let you hear, and what he concealed from us, we conceal from you. If you add nothing to Umm al-Qurʾān (al-Fātiḥah), it suffices, and if you add to it, it is better.” Narrated by al-Bukhārī.
Shaykh al-Islām Imam al-Nawawī (may Allah have mercy on him) said in al-Majmūʿ (Vol.3/389): “The sunnah is to recite aloud in the two rakʿahs of Ṣubḥ (Fajr), Maghrib, and ʿIshāʾ, and in the Friday prayer, and to recite silently in Dhuhr, ʿAṣr, the third rakʿah of Maghrib, and the third and fourth of ʿIshāʾ. All of this is by the consensus of the Muslims, together with the mutually reinforcing authentic ḥadīths on the matter. This is the ruling for the imam. As for the individual worshipper (munfarid), it is sunnah for him to recite aloud according to us and according to the majority… If he recites aloud where silence is prescribed, or the reverse, his prayer is not invalidated, nor is there a prostration of forgetfulness (sujūd al-sahw) for it, but he has committed something disliked (makrūh).” And Allah Almighty knows best.
Is the son of the sister by breastfeeding considered a mahram in Islam, and is it permissible for a woman to go for Hajj with him?
Everything that is prohibited by lineage is also prohibited by breastfeeding. The son of the sister by breastfeeding is considered a mahram, just like the son of the sister by blood, and it is permissible for him to be her mahram for Hajj and Umrah. And Allah Knows Best.
What is the Islamic ruling on the Udhiyah (sacrificial offfering)?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
The Udhiyah (sacrificial offering) is a Confirmed Sunnah (Sunnah Mu’akkadah) for every adult Muslim of sound mind who possesses the financial means, whether they are a resident, a traveler, or a pilgrim (Haj). This is based on the statement of the Prophet ﷺ: 'When the ten days [of Dhu al-Hijjah] begin and one of you desires to offer a sacrifice, let him not touch [cut] anything of his hair or skin' [Narrated by Muslim].
The point of evidence (Wajh al-Dalalah) here is that the Prophet ﷺ linked the sacrifice to the individual's will and desire by saying, 'and one of you desires.' This indicates that it is not obligatory (Wajib); had it been mandatory, he would have simply said, 'let him not touch his hair until he sacrifices' [without making it conditional upon desire].
Furthermore, it is narrated that Abu Bakr and Umar (may Allah be pleased with them both) would sometimes refrain from offering the sacrifice out of fear that people might mistakenly view it as an obligatory duty [Narrated by al-Bayhaqi and others with a good (Hasan) chain of transmission]. And Allah the Exalted knows best.
"If the fidyah becomes obligatory upon a pregnant or nursing woman because she broke her fast out of fear for her child, is it obligatory from her own wealth, or from her husband's wealth?"
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
The fidyah (ransom/compensation payment for breaking the fast) is obligatory from the wife's own wealth, and is not obligatory upon the husband unless he voluntarily chooses to pay it on her behalf.
It is stated in Mughnī al-Muḥtāj (Vol.2/P.174): "If the two [the pregnant woman and the nursing mother] fear for the child alone — such as a pregnant woman fearing miscarriage, or a nursing mother fearing that her milk supply would decrease, thereby endangering the child — then both the qaḍā' (making up the missed fast) and the fidyah become obligatory upon them, to be paid from their own wealth." And Allah, the Exalted, knows best.