Certainly, he will surely learn it the hard way. That's if he hadn't already given the timeline of this post and the OP. Traders who have the mindset of always winning are those who feel it's an aberration to record a loss and they tend to jettison the idea of using a SL. Often these traders are ruined. Let me speak from the experience of an FX Trader, no matter how small a lot size one wants to use to avoid using a SL one will soon discover the hard reality of either a trade running for a long time without making profit or account getting burnt eventually. It's best to use SL while trading as it gives traders peace of mind. Yes, quiet alright SL may be hit but that's what trading is also about. A trader who doesn't want to record a loss will eventually end up a loser.