There's nothing necessary to quit bitcoin trading, because if you can spend more time over the observation of price movement even if price goes down, can make a profit out of it.
Yeah, if he lost then i does not mean that trading is a place of losers, but he will have to change his strategy and have to adopt some other market and some other strategy for getting profit from trading, it just require some knowledge, skills, intelligence and a good time to give to there to earn a bigger profit from trading.