What are the Sunnahs and etiquettes related to the slaughtering of an animal?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
1-The animal should not be terrified or frightened before it is slaughtered.
2-An animal should not be slaughtered in front of other animals.
3-It is recommended to offer water to the animal before it is slaughtered.
4-The knife must be sharpened before the slaughter to ensure that the esophagus, trachea, and jugular veins are severed as quickly and cleanly as possible. This is based on the Prophet’s (peace be upon him) saying: "Verily, Allah has prescribed Ihsan (excellence/proficiency) in all things. So, if you kill, kill well; and if you slaughter, slaughter well. Let each one of you sharpen his blade and let him spare the animal unnecessary suffering." [Narrated by Muslim].
5-One must not begin skinning or butchering the animal until its death has been fully confirmed.
6-Cows and Sheep: It is best to slaughter them while they are lying on their left side, facing the Qiblah. The right hind leg should be left untied so the animal can move it, which helps it remain more comfortable during its final moments. Unlike other livestock, it is preferred to perform Nahr (slaughtering by a swift stab at the base of the neck) while the camel is standing, with its left knee tied. And Allah the Almighty knows best.
Is it permissible to pay the Zakah (obligatory charity) for settling the debt of a deceased relative?
It is impermissible to pay the Zakah for settling the debt of the deceased since Zakah is paid to eligible recipients who are alive. As for the debts of the deceased, they are to be settled from the estate before dividing it amongst the heirs, but if the deceased didn`t leave an estate, then it is desirable for his/her heirs to settle those debts if they can afford them. And Allah Knows Best.
What should a person, who doubts the validity of his Wudu, or over performs it, do?
One who doubts the validity of his/her Wudu while performing it should redo it until he/she is certain of having attained purity. But, if doubt was after having performed Wudu, then he/she should not pay attention to that as doubt after the end of an act of worship does not count. This is of course in case doubt was within the reasonable limits since once it goes beyond that, it becomes a whispering of the Shaytaan (devil) which he/she should ignore as the Wudu is valid.
Is it permissible for one to give the Zakah (obligatory charity) to his indebted brother?
It is permissible for one to give the Zakah to his brother if he was indebted, or poor.