Praise be to Allah.

The evil eye is real as the Prophet (peace and blessings of Allah be upon him) told us, and the way to protect oneself against it is by reciting the ruqyahs (incantations) that are prescribed in sharee’ah (Islamic law) and by reciting the words of the Prophet (peace and blessings of Allah be upon him), not by using amulets or by using the charms written by liars and charlatans. For more information about the evil eye and the ways of protecting oneself against it, please see question no. 20954 and 11359.

Carrying amulets and charms for the purpose of protecting oneself against the evil eye and witchcraft comes under the heading of wearing amulets which is forbidden. It was narrated from ‘Uqbah ibn ‘Amir al-Juhani (may Allah be pleased with him) that some people came to the Messenger of Allah (peace and blessings of Allah be upon him) and he accepted the oath of allegiance from nine of them and not from one man. They said: O Messenger of Allah, you accepted the allegiance of nine and not from one. He said: “He is wearing an amulet.” So he put his hand in (his garment) and broke it, then he accepted his oath of allegiance and said: “Whoever wears an amulet has associated others with Allah (shirk).” Narrated by Ahmad (16781); classed as saheeh (authentic) by al-Albani in al-Silsilah al-Saheehah (492). 

Ahmad also narrated that ‘Uqbah ibn ‘Amir (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: “Whoever wears an amulet, may Allah never fulfill his wish and whoever wears a seashell, may Allah never protect him from what he fears.” This hadeeth (narration) was classed as hasan (sound) by al-Arna’oot in his commentary on al-Musnad. 

Seashells were worn to ward off the evil eye. 

Al-Khattabi (may Allah have mercy on him) said: Amulets were things that they used to wear in the belief that they could ward off calamity. 

Al-Baghawi (may Allah have mercy on him) said: The Arabs used to put amulets on their children to protect them against the evil eye, or so they claimed. This was declared invalid by sharee’ah.

The correct scholarly view is that amulets are forbidden even if they are composed of words from the Quran. See question no. 10543. As for those that contain unknown letters and words, there is no difference of opinion; they are haram (impermissible) and there is no guarantee that they are not magic or that they are not seeking the help of the jinn.

Thirdly:

The way to get rid of amulets and magic when they are discovered is by undoing the knots – if there are knots – and separating the pieces, then destroying them by burning and the like, because it is narrated that Zayd ibn Arqam (may Allah be pleased with him) said: A Jewish man used to enter upon the Prophet (peace and blessings of Allah be upon him) who trusted him. He tied some knots and placed them in a well belonging to a man from among the Ansar (inhabitants of Madinah who welcomed the immigrants from Makkah). He suffered because of this for several days – or, according to the hadeeth of ‘Aishah (may Allah be pleased with her), for six months – then two angels came to visit him. One sat at his head and the other at his feet. One of them said, “Do you know what is ailing him?” He said: “So and so who used to enter upon him tied some knots for him and threw them into the well of so and so, the Ansari. He should send a man to him to take the bundle out, and he will find that the water has turned yellow.” Then Jibreel (peace be upon him) came to him, bringing the revelation of al-Mu’awwadhatayn, and he told him that a Jewish man had bewitched him and that the materials used were in the well of so and so. Then he sent a man – according to another isnad (chain of narration), he sent ‘Ali (may Allah be pleased with him) – who found that the water had turned yellow. He took out the bundle and brought it to him, and he told him to untie it and recite a verse of Quran. He started to recite and untie it, and every time he untied a knot, he felt a little better, until he was fully recovered.” 

[al-Haakim, al-Nasaa’i, Ahmad, and al-Tabaraani]. 

Shaykh Ibn Baz (may Allah have mercy on him) said: Efforts should be made to find out what the witch has done. If he has put some hair, for example, in a certain place, or put it in a comb and so on, if it is known that he has put it in a certain place, it should be taken out and burned or destroyed. Then its effects will be cancelled out and what the witch wanted to do will be annulled.

So to get rid of the paper that your father has, tear it up and burn it, and remind him to repent to Allah from having worn an amulet. 

And Allah knows best.