All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If it is confirmed by trustworthy people who treat the people possessed by jinn that socializing with them [people possessed by jinn] may be harmful, then a Muslim should avoid the person who is possessed by jinn and be careful to avoid his harm, that is to take every permissible means (for prevention). Allaah Says (what means): {And do not kill yourselves (nor kill one another). Surely, Allaah is Most Merciful to you.}[Quran 4:29] Also, it is confirmed that the Prophet said: "There should be no harm nor reciprocal harm.” [Ahmad]
Indeed, the Prophet used to take the necessary means of protection although he was the best person who relied on Allaah and the best person who mentioned Allaah most. As-Saa’ib ibn Yazeed narrated that "the Prophet wove two armors on the day of Uhud.” [Ahmad]
As regards your second question regarding the verse in which Allaah Says (what means): {And believe in what I have sent down confirming that which is [already] with you, and be not the first to disbelieve in it. And do not exchange My signs for a small price, and fear [only] Me.}[Quran 2:41]; then Al-Qurtubi summarized the meaning of the verse and said: “Although this verse was revealed about the Children of Israel, yet it applies to those who do the same act like them. If a person takes bribery in order to change a right or annul it, or he refuses to learn what is an obligation on him, or do what he knew that it is an obligation on him but he does not do it until he takes a fee for it, then he is included in the meaning of the verse.”
As regards selling the Mus-haf (the Arabic text of the Quran), then this is permissible according to the view of the majority of the scholars . However, it is not permissible at all to give the Mus-haf to a non-Muslim as we clarified in Fatwa 86200.
Nonetheless, a non-Muslim is permitted to read and touch the translation of the meaning of the Quran because it is not a Quran. It is for this reason that the jurists said: “It is not forbidden for a person in a state of sexual defilement, a menstruating woman and even a non-Muslim to read the translation of the meaning of the Quran.”
Since selling the Mus-haf is permissible, then selling the translation of the meaning of the Quran is permissible with greater reason. Therefore, it is permissible for a Muslim to benefit from what he obtained from the price of the Mus-hafs and books or donate it – if he so wishes – and this is not included in the previous verse.
Allaah Knows best.