This sucks, I see stories like this all the time on here. He really shouldnt have been keeping that amount of crypto online though. It should be on paper wallets or a hardware wallet. Sad for him 
I completely agree with you. Keeping such an amount of money and not securing yourself is a big nonsense. But the second side of the coin is to replace SIM cards. How can these substitutions be prevented? Indeed, there have been a lot of victims of fake SIM cards lately.