Praying behind someone hanging amulets

Q 4: What is the ruling on using amulets and words of protection in Islam? Should I observe Salah (Prayer) behind an Imam who seeks treatment through them? Am I considered sinful if I observe Salah behind him after I know this about him? A: Amulets and words of protection are of three types: The first type: Amulets and words of protection that involve Shirk (associating others with Allah in His Divinity or worship) (Part No. 1; Page No. 122

A: Amulets and words of protection are of three types: The first type: Amulets and words of protection that involve Shirk (associating others with Allah in His Divinity or worship) (Part No. 1; Page No. 122) like Istighathah (imploring) anyone other than Allah and supplicating to anyone other than Allah including Jinn (creatures created from fire), devils, Awliya' (pious people), and righteous people. It is not permissible to write or use such amulets and words of protection as they associate others with Allah in His Divinity or worship, and whoever writes, uses, or promotes them is considered a Mushrik (one who associates others with Allah in His Divinity or worship) behind whom observing Salah (Prayer) is not permissible. The second type: Amulets that contain separate letters, talismans, intelligible words, or any beads and cowrie shells or the like are forbidden. Even if the people do not believe in their good or evil but that they are a reason, putting them on is still considered minor Shirk (associating other partners with Allah that is not tantamount to taking the Muslim out of Islam); as the Prophet (peace be upon him) says, If one ties an amulet, Allah will not accomplish his affairs for him and if one ties a cowrie shell, Allah will not protect him. In another narration, Anyone who wears an amulet commits an act of Shirk. Putting them on may be considered major Shirk (associating others with Allah in His Divinity or worship that takes the Muslim out of Islam), if people believe that they themselves ward off evils, and are not just a means for that.Whoever writes such amulets should be advised and warned about doing so. He should respond or the official authority will depose him from leading congregational prayer to prevent people from taking him as an example and imitating him. Observing Salah (Prayer) behind him is considered correct if he does not believe that such amulets themselves are able to benefit. The third type: Amulets and words of protection from Qur'an and lawful supplications written in Arabic words - these are a point of disagreement among the scholars, as there are two opinions: (Part No. 1; Page No. 123)  The first opinion: They are permissible because they are void of Shirk and its means. The second opinion: They are unlawful; as the Prophet (peace be upon him) generally forbade us from putting on all types of amulets and warned us against them. For example, the Prophet (peace be upon him) says, Ruqyahs, amulets and love-potions are [acts of] Shirk. Moreover, the Prophet (peace be upon him) says, If someone ties an amulet, Allah will not accomplish his affairs for him and if someone ties a cowrie shell, Allah will not protect him. This opinion is the right one due to the general purport of the Hadith banning the use of amulets.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.