Is sorcery, through the use of jinn, real, and is it undone by the jinn's departure from the body?

Shaykh al-Islam Ibn Taymiyyah mentioned that the use of jinn in sorcery is forbidden, just like unlawful killing, or causing illness, or preventing sexual intercourse, or instilling hatred, or causing attraction; this is sorcery.

The treatment for someone afflicted by a jinn possession is as follows: 1. Addressing the jinn and requesting its departure from the body, and clarifying the unlawfulness of its action, as was done by the Prophet, peace and blessings be upon him, and by Ibn Taymiyyah. 2. Extracting the sorcery and nullifying it, if it is possible to access it. 3. Treatment with lawful ruqyah (incantations), protective supplications, permissible medicines, and supplications.