Before studying about this type of dark illusion, we need to keep in our heads, that it isn’t confirmed the person might be suffering from this. It is also a possibility that he/she is suffering mental illness. Nevertheless, continuously reciting verses from the Holy Quran won’t hurt him, but it will as an alternative heal him, if the grounds for delusion/s really are jinn [Demons].
The Holy Prophet (Peace be upon him): “If anyone of you dream something and you like that dream, it is blessed upon you from Allah. He is supposed to praise Allah for it and he should speak about it to fellow men. If he dreams of something he dislikes, it is from Satan. He ought to search for sanctuary in Allah from it and not state it to anyone. Thereby, it will not damage him.” Recorded in Sahih al-Bukhari.
SYMPTOMS OF SIHR (MAGIC) OF BAD DREAMS & HEARING VOICES

1. Constant nightmares on the victim.
2. The victim observes someone calling him/her in his/her dream.
3. The victim experiences voices in his head but he cannot see anyone around him talking to him.
4. The victim often experiences unexplainable whispers.
5. The victim is very suspicious about people close to him/her.
6. The victim might experience dreams that include falling from a huge height.
7. Constant dreaming of getting chased by a carnivore.

Any normal person can see these dreams – that in addition from Jinn; but that doesn’t signify that he is under a curse or a spell for having dreams like these. Nevertheless, if the regularity goes higher, there’s a possibility that this is the job of a Dark Illusionist.
HOW DOES THE SIHR (MAGIC) OF BAD DREAMS & HEARING VOICES TAKE PLACE?

The practitioner of the dark illusion trains a demon to become visible to a human being mutually in hallucination and in realism, in the outward appearance of savage monsters assaulting him; to call him when wide awake in noises which he distinguishes and which he doesn’t; to base him/her to believe public that are particularly close to him/her in person and people who are not.