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
I can't see the point. Why should one not open multiple trades? For me I often practice DCA in spot trading, when BTC moves. Up or Down. It's nothing special about opening 20 or more trades that way. Some get hit, some not. It's very easy to check them once a day and place new orders. Tools nowadays are good enough to handle this. If you like to give some advice, don't give him this one. Maybe you should first ask your friend, how he likes to get some profit. Does he follow a strategy or not?