Who is the one required to slaughter the 'aqīqah?
All praise is due to Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
It is Sunnah for the 'aqīqah to be slaughtered by the guardian of the newborn — the one upon whom the child's financial maintenance is obligatory — provided he is financially capable of doing so. 'Alī ibn Abī Ṭālib, may Allah be pleased with him, reported: "The Messenger of Allah ﷺ performed the 'aqīqah for al-Ḥasan with one sheep." — Narrated by al-Tirmidhī. And Allah Almighty knows best.
I own a pharmacy and have only merchandise. A full year (*ḥawl*) has passed and I have no cash. How do I pay the zakāh?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Zakāh must be paid immediately from the day it becomes due, and delaying it is forbidden when one is able to pay it, because it is the right of the poor, and it is forbidden to delay giving people their rights except for a valid Sharīʿah excuse. Shaykh al-Islām Imam al-Nawawī (may Allah have mercy on him) said: “In our school, zakāh must be paid out immediately. Once it becomes due and he is able to pay it, it is not permissible to delay it. If he is unable, he may delay it until he is able. If he delays it after being able, he is disobedient and becomes liable for it.” [al-Majmūʿ Sharḥ al-Muhadhdhab, Vol.5/p.333]
If cash is not available to pay the zakāh and the only option is to pay in installments, he must pay it, even if in installments, from the proceeds of the merchandise that is sold after the time the zakāh became due, by deducting a set amount from each day’s takings. And Allah Almighty knows best.
What should one who doubts the validity of his ablution and performs it frequently do?
Whoever doubts the validity of his ablution after finishing it, his ablution is valid. This is because the default is the validity of the ablution, and because doubt after finishing an act of worship doesn`t affect its validity. And Allah the Almighty knows best.
Is it permissible for a woman to sit with her brothers-in-law?
It is impermissible for a woman to sit with her brothers-in-law, and it is also impermissible for a person to have a Khulwa (seclusion) with his sister-in-law.