I prefer to have a regular job, have a permanent stable earnings, save it and invest it in bitcoin. While it seems to me more rational. However, you can devote all your time to studying bitcoins, the financial market, the stock exchange and make it your own way of earning - I have a friend who works that way.
Making money in bitcoin simply by investing money in it and doing nothing, however, I prefer to view this currency as a long-term investment that will ensure my future.
Yeah it would be my choice too, whats good thing about it is we can both earn from our salary and Bitcoin online. The key here is time management as many people think here that its not possible to squeeze anything related to Bitcoin because they have a job. As for your friend what he is doing is the right path of becoming a good investor as people who buys first before even analyzing the investment cannot be called a wise investor. I just hope you find a way to earn in both ways.