Couple reasons, why EA results from back test didn’t match to live trading:
ex4 format has been created for developers who want to protect their intellectual property, so if developer allowed you to change inputs it is ok, if no, you will not get access to it because ex4 is encrypted format .
Hi! 
In my opinion, there are 2 things mixed by your friend. On one hand he has EAs and on the other hand he turns them off because of some reasons that happen in the market. But this is how discretionary traders would act.
But EAs have been tested over a long period of time in the best case so you can see how they react in crises! My EAs are tested with Dukascopy data starting in 2003. And since 2003 until now, there have been several crises. 
If they pass those, then I assume they will pass other crises as well.
With your friend, it looks to me like he needed an excuse for his vacation where he couldn’t supervise the EAs. But if someone has to supervise his EAs, then they are definitely very dangerous EAs that I would keep my hands off of!
As Hal is a millionaire and managing the 18th largest fund at ICMarkets for his clients and hedge funds, and as he has been trading profitable FX majors for decades, his being careful approach to protect his clients is his choice.
The major issue is whether the USD, GBP , EUR, JPY & CAD economies are steadying inflation. IMO, while the Ukraine war lasts, and the major banks are not over-reacting every ten minutes, the FX market will settle down to what was normality before Covid and global warming.
However, us retail traders are not in the fundamental loop that Hal has daily access to. In his opinion, only the big boys know the seriousness of what’s going on and we small frys do not.
Hope that helps.
I cant remember asking you for any! even someday , if I want to ask someone, that person could be anyone, but not you. I can clearly remember that you were celebrating your success because your SL was not triggered yet, and you were still in loss! I do not seek advice from your type of professor 
Thank you great behavior, I’ll show you mine too
I have seen your expertise in trading, that has been enough for me. no need to see anything more, and do me a favor, do not reply me, cause im here to learn trading, you cant add a single point to what I already know.
Ouch! 
Interesting perspective.