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
You can't advice it to anyone to stop doing multiple trade at a time. Though if you are talking to a newbie, I believe that trading a single coin at a time and familiarizing that certain coin at a time would be beneficial to him long term. Managing multiple trades is hard it's like that you are multitasking every time though it's a faster way of making profits if you know what you are doing. This is why long term traders or veteran traders doesn't stick with a single monitor thus they always have at least 2 or 3 monitors in their computer set up since it can help them watch every trades they are doing. A newbie trading a multiple coin at a time will just make it hard for him to understand what he is doing given that the information he is consuming is so much from his understanding and it can cause a losing trade.