Silicone Valley injecting blood

Silicone valley is buying young people's blood (https://www.usnews.com/news/health-news/articles/2019-01-17/startup-offers-young-blood-transfusions-to-rejuvenate-the-body) to maintain their youth and vitality. So these elites admit that they believe young blood helps them live longer. This is not even some kind of conspiracy theory. It's literally something that is happening. But what if there's more behind this than just transfusions? How would we know? Would they tell us? Or would they simply hint at it through symbolism?
How can you prove something as sinister as this?