If people will leave their current jobs just to focus and work with cryptocurrencies, I think they need to work hard to be a successful person or they can also work as developers or as a trader. This is the best thing to do if they want to make the bitcoin as their source of income.
He should have an expertise in any of source in bitcoin. Because if he is already decided to do so or after thinking that he will quit his current job.
Think about the worst case scenarios that might happen and also think about those positive ones, it's like a gambling.
But if you think that you have assurance that your life will be good for doing that, it's better.