My friend loves opening different trades at a time, most at times is difficult for him to control what's should be. Trading on free chart with multiple opening can be very dangerous. Yesterday he experience unusual hit when bitcoin price drops again, four trades loss at once when the market go against him. Personally I don't advise multiple trade especially when you're not familiar with trade
The issue with your friend isn't that he placed multiple trades. What happened was that he didn't apply Money Management principle. Everyone who trades multiple pairs at the same time knows how to reduce and control their risk. He should determine whatever he's going to lose (in case it goes wrong) or it goes well in profit. The major issue in trading isn't the profit but the loss side of it.