That is unfortunate, I hope your friend's friends recover financially
and mentally. You can also tell your friend to stop beating himself up. Sure he was the one who introduced them to Luna (and it was definitely not a good advice) but they are the ones who decided to risk their money for what is clearly hyped up shit.
The LUNA scandal reminds me of BitConnect, just in another form. Those who learn their lesson are the not the targets of these, it is the newly joined users or no-coiners who start their journey in crypto via such scams, sadly.
I think that's how it really is. People who are familiar with even just bitcoin for 2-5 years would have already learned that these alts are nothing but things to pump and dump, and wouldn't have risked a lot money if they ever "invest".
Moral of the story: Don't risk money you can't afford to lose. Till the next big scam.