How did your friend become successful so quickly from Bitcoin? Did he invest in Bitcoin? Or did he trade with Bitcoin? Bitcoin can never make a person successful or rich quickly. I think your friend is gambling or trading with Bitcoin. Otherwise, it is not possible to achieve success so quickly. If you think that the way to become successful quickly from Bitcoin is to gamble or trade with Bitcoin, then I warn you. Your friend may be going to face losses very quickly. There is no way to become successful quickly from Bitcoin.
Never take any big steps even after seeing the short-term success of others. First read about Bitcoin and study how Bitcoin works. I think you may be telling a fabricated story or your friend has taken a risky step, where your friend is lucky and has not started losing money yet. Maybe it will happen very soon. Because, there is no way to become successful quickly from Bitcoin. Even keeping all your money in Bitcoin is a riskier move.
That what comes my mind, because have not seen someone successful in bitcoin easily except is a trader or gambler, because that is the only thing that i can believe that make you get easily profit in bitcoin. But if is investment you need to invest for the long term before you can succeed in bitcoin, is not like other shitcoins that increases or decrease easily he take long term before he pump, and all is gradually process. So am surprised how your friend successful so easily in bitcoin without facings the challenges, bitcoin is volatile and is different from other coins so is very difficult to gain huge profit in bitcoin if is investment method. And if is a traders he should always minimize is risk, because he can probably lose all is funds when the market is bad. Trading is risky and you can be profitable easily and that is how you will lose too. because the market is always unpredictable except you are lucky trader and have the experience to analyse the market very well.
It's actually a good and exciting thing to see someone progress fast like that, but he quit selling artworks and other little businesses that kept him going he stopped, he now depends fully on Bitcoin.
You friend took wrong decision buy just depending on bitcoin and leave is business because he achieve huge profit on is first day in bitcoin. you need to know that anything that bring profit, investment, business or trading all as is on risk. your friend needs to go back to is business so that the business will be helpful for you him one day. Because bitcoin can't guarantee you that you will continue getting huge profit. You will usually hear that investors always advice newbie to have source of income before they invest or trade with Bitcoin, because of the risk involved. your friends have business that is managing because he get profit on is first day on bitcoin he leave is business and focus only on bitcoin. I don't think is a good idea to leave your business and focus on one thing, because he can fail anytime, so you need to have other source to make everything balance for you in the future.