What is the ruling on one who issues fatwas while not praying, and what is the ruling on his advice if it is correct, and is it obligatory to listen to his advice?

Al-Bukhari narrated that Abu Hurayrah (may Allah be pleased with him) heard from a devil his statement: "When you go to your bed, recite Ayat al-Kursi, a guardian from Allah will remain over you, and no devil will approach you until morning." The Prophet (peace and blessings be upon him) confirmed him, saying: "He has told you the truth, though he is a great liar. That was a devil." Ibn Hajar mentioned that the devil may teach what benefits the believer, and the believer should seek out the benefit and act upon it, and the state of the one who taught it to him does not harm him. He must also advise the one who benefited him.