Apart from losing some small amounts to gambling, the most stupid thing I did was bepositing my BTC on a trading site having no previous experience in trading. Of course I lost all my money in one day. Fortunately it was not over 0.01 but still, that was stupid.
Investing in trading is never a bad thing! Don't tell him that! At least he had a try at how to trade and had a feel for it. That 0.01 btc loss can be considered as part of the learning curve. Just go with it. Don't be afraid to lose a few bitcoins to learn. When you have the hang of it, you'll get more from your trading experience.
I personally think that those people who trade blindly is an ex of gambler they just looking for a luck
I prefer to go straight gambling rather than have to trade blindly.