The patient goes through epileptic seizures, and the Jinn that has been appointed to the task of Sihr speaks through the patient. This is when you should deal with the Jinn. You should ask the jinn several questions. Remember, if the jinn denies answering the unnecessary questions then do not force him and proceed further.
If he does not respond to the first two questions then you can come to the third question and ask him why he has possessed the patient. But first, if he mentions his religion Islam, then you should teach him the rulings of Islam and that a Muslims should not bother another Muslim and that it is Sinful. However if he is not a Muslim then invite him to Islam.
After you confirm whether he is a Muslim or not, you may then ask why the jinn has possessed the person. It might be for several reasons, mainly:
If the jinn says that he is in love with the patient, you should convince him. This is done depending upon the second question about religion. If Jinn is a Muslim, you can tell him that it is sinful to harm other Muslims, or anyone. If he is not a Muslim then you might have to be strict and tell him that you will burn him with the words of Quran. Keep in mind that, recitation of the Quran burns the evil-jinn. So incase the jinn does not agree on leaving, you may want to recite/repeat the Ruqya.
Now if the jinn works for a Witch, you would then require asking him where the Charm (Key/Amulet/Taweez) is buried/hidden. Always remember to confirm where it is buried before you let the jinn go since these jinn tell many lies. So it is better to confirm if the charm is found, and once found it should be destroyed in the following way.
Take some water in a bowl and recite the following verses in a way that the air from your mouth touches the surface of the water.
Now take the charm, let it be Ink, paper, perfume, and dissolve it in the water on which you recited the Verses above. Then spill that water at a distant location. Once the charm is removed, you should convince the jinn never to come back to the patient again.
If the Magic has been done through traces of hair/nails, then recite the above verses over water and tell the patient to drink from it and wash himself with it. It is fine to pour this water into more water to take a bath with.
If the Magic has been done through food/drink then the patient should feel pain in his stomach, in that case you do the same as above. If the pain continues, it is best to take some Senna leaves and bowl them in water. Recite the above verses and drink from it. It is the best laxative and it has no side effects. Used in all laxative medicines. You can add honey to sweeten it if the taste is bitter.
After the jinn is gone, tell the patient to listen to Ayat-ul-kursi three times every day for a month at least. It is required to check on the patient after a month and to recite the Ruqya to him just to make sure that the Jinn has left. If the patient does not feel uneasy and does not become epileptic then All praise is for Allah. If not then repeat the above.
And Allah is the Hearer of All.