You should give him an advice if you are true friend of him, just tell him the chances that his money possible to lost if the bitcoin decrease the value. But in the end it depends on him if he continue to invest in bitcoin or better if he going to learn more about it so that he have knowledge and he can use it in investing when o here to invest.

We all know investing in bitcoin is really good and gives  a good profit but also it is very risky because of the price of it is increasing and decreasing that possible for the investors to earn money or losing his investment.