What should we do to treat envy if the envier is not a Muslim (Christian), and is it permissible to take from his ablution water?

The evil eye can afflict from a disbeliever just as it can from a Muslim, based on the Almighty's saying: "And indeed, those who disbelieve would almost make you slip with their eyes," and the Prophet's (peace and blessings be upon him) saying: "The evil eye is real." If the disbelieving afflicter is known, it suffices to wash something from his body, or something that directly touched his body, such as a undershirt or a skullcap. Alternatively, wet earth upon which he walked, or tissues he used, can be taken, placed in water, and then poured over the afflicted person or drunk by them. The Permanent Committee and Ibn Uthaymeen have mentioned this method, stating that it is tried and beneficial, by the permission of Allah.