Is what happens to a young man—hearing voices that tell him about unseen matters, such as the death of a person or their illness due to sorcery, and these matters later come true—considered polytheism (shirk) or fortune-telling (kahana) that necessitates shunning him and warning against him?

A believer is tested to elevate their ranks and expiate their sins. What happened to the questioner could be psychological obsessions or satanic whispers to fall into magic, which is disbelief. Therefore, one must resort to Allah Almighty, seek refuge in Him, increase His remembrance, and associate with the righteous. As for the actions of the friends and students of knowledge, they are incorrect; it was obligatory upon them to cooperate in righteousness and piety, not in sin and aggression.