John McAfee is another one of these idiots that got rich during the dotcom bubble, and since they are so rich and bored, they spend their day on twitter talking about any trending subject, in this case Bitcoin.
John McAffee is a joke when it comes to BTC. Let him talk, he knows nothing.
This is the quote that OP is talking about:
He didn’t specify if he will mine either BTC-ABC (8mb blocks) or Btc1 (2mb/SW) or (1mb/sw) but rather chose to follow only Jihan's fork simply because “I'm not an idiot.” While he maintains that only Jihan's fork will have value, he notes that there will be a huge damage to the main Bitcoin and its price “may go back to $40.”
Within the given projected period, McAfee puts the Ethereum price at somewhere between a penny and $200,000.