Q 3: Is it permissible to pray behind
a person who eats the meat of animals slaughtered for anyone other than Allah
and yet claims to have pronounced the Name of Allah at the time of slaughtering?
Offering Salah behind a person who slaughters animals for anyone other than Allah such as Jinn is not valid, even if he mentions Allah's Name when slaughtering the animals. This is an act of Shirk (associating others with Allah in His Divinity or worship) and this person's Salah is not valid, because he is a Mushrik (one who associates others with Allah in His Divinity or worship) and so is the Salah of any person who slaughters animals for other than Allah (Exalted be He), even if they mention Allah's Name before slaughtering. Allah (Exalted be He) informs us of this in His Statement:
...on which Allâh’s Name has not been mentioned while slaughtering).
According to the statement of the Prophet (peace be upon him),
The reward of deeds depends upon the intentions and every person will get the reward according to what he has intended.
This person has slaughtered the animal to draw closer to the Waliy, Jinn or any other being, such as angels, idols and the like.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.