Is the effect of the Qur'an on those afflicted by sorcery, and the expulsion of jinn from them, considered tangible proof of the Qur'an's truthfulness? Can this evidence be used in dawah (inviting others to Islam)? Is what happens a reality or merely a psychological illness? Are there similar cases in the West?

The effect of the Quran on the one being ruqya-ed is evidence of its merit, but it is not sufficient to prove that it is a revealed revelation, as this effect may occur with non-Qur'anic supplications. There is abundant clear evidence proving the revelation. As for the jinn speaking through the mouth of the afflicted person, this is common, and there is no text that confirms or denies it, but many ruqya practitioners, including Wahid Abd al-Salam Bali, who are among the people of knowledge and da'wah, have mentioned it. There is no information about similar cases in the West.