Is one who warns his family and friends against a preacher—after discovering that his narrations are weak or fabricated, and after being affected by them himself, which caused him a setback—sinful for fearing that they experience what happened to him?

Mentioning weak hadiths in sermons, encouragement, and the virtues of deeds is not considered reprehensible by many scholars, unlike fabricated hadiths, which should not be mentioned except to expose their fabrication and warn against them.

If the preacher generally presents good discourse but does not verify what he narrates, then his situation must be clarified, and it should be stated that what he possesses is generally beneficial, but one must be cautious about the hadiths he narrates until their authenticity is verified. He can also be advised to seek out the authentic and good hadiths, and those that scholars are lenient in narrating, as long as they are not fabricated.