Can jinn inhabit a person's brain or any of their organs? And if so, how does possession occur? Can jinn repent, or is the Qur'an the only way to expel them? Does a person's lack of cleanliness affect the jinn's continued presence within them?

Jinn can enter and possess the human body. This is affirmed by the Quran, the Sunnah, and the consensus of the early generations of the Ummah. It is a well-known and palpable phenomenon, where the jinn enters the afflicted person and speaks through their tongue. It is authentically reported that Satan afflicts a person whom Allah allows him to affect with a touch, thereby stirring up the dark humors and vapors that rise to the brain, causing epilepsy and erratic behavior. As for the jinn dwelling in specific organs such as the brain, eye, or ear, there is no specific text that either confirms or denies this.