I was like what could be the problem or could it be that some people already gotten information about him to have come to rob him this way?
This easily speak to me that is a results of his showy lifestyles and if he is that calm or doesn't always show off about his bitcoin investment there wouldn't had been a day such incidents could had happened to him, or just imagine I came out with my phone i could have also lose my phone. The funny thing is that he doesn't leave his assets into a non custodial wallet, instead he keep saying that he preferred leaving his assets into exchange to enable him to trade when the market requires to trade or when their is a sharp buy or sell. But now, he lost everything; his phone, assets.
Well, he may not have actually lost everything as you said, he simply lost his phone and that's it.
If your friend has a lot of money and doing well as you made us believe, then he must be using a high end phone, which simply means that the phones security would be high or a top notch depending on the make and product.
If the above be the case, and the phone is locked when the robbers snatched the phone, they will have no access to the data contained inside the phone until the flash it, which permanently erases the data on the phone leaving the robbers with a brand new-like phone in terms of os and software, to access any of your friends private account on any platform or exchange, the robbers will need his login details which includes email address and password, and maybe a 2fa code which is a mandatory requirement for most top crypto exchanges this days.
So, for now, it's wrong to say or assume that your friend lost everything, he simply lost his phone, which he can get another and recover back his trading Funds and accounts.
But all the same, I get the message, which is that we all should be careful how we show ourselves or go out at night, thanks very much for the advice.