I read it here before but the best way is deconstructing a specific case of the person in question choosing. The problem is that replacing one influencer with another one won't change the understanding issue of misplaced trust in media/people.
I think that these things should be voluntary by the way. Both for success chances and pure respect for your sibling.
Ask him if they would be interested. Then make them choose an episode. Prepare yourself. Ask them to prepare a little document in which they express their understanding and lesson that they learned from the episode. Ask them if they are willing to investigate how true these things are. Look for evidence together or alone. When done, get together and talk about the truthfulness of the ideas.
Alternatively ask yourself if they have some kind of expertise in something and look if there is a Joe Rogan episode about and suggest them to watch it. The deconstruction would happen automatically. You can help by ask them questions about it. Having to vocalize criticism towards something is an amazing reflection exercise.