I personally think having this discussion on the internet is overwhelmingly pointless since people will just believe anything and then won't be shaken in that belief once it takes hold.
But specifically about what RFK said, that's not true. RFK has said that people should personally go up to strangers in the street to tell them not to vaccinate their children at all, and that he does so himself. And that if enough people pester random parents about not vaccinating, the child could be "saved".
He also said that there is no vaccine that is safe and effective and he claimed that some vaccines cause cancer without proof.
Whenever he claims that he didn't say those things, it's either the effects of his brain worm or he's just lying to appear more moderate in front of mainstream audiences.