I will suggest you to start a large number of different small businesses, like start a faucet, invest some other in starting a computer academy(which do not require big money), also start a blog, plus invest in some companies, buy shares from already established businesses, you will be successful.
Yes, a large number of businesses benefit more but he have only 13 bitcoins and with that I think he do not start much more businesses, he can invest it on a few places and after that he will have to spread the circle of his business.