I can't access the site either.
I've heard of this from a few immoral youtube users trying to promote this scam, so that they can earn their affiliate link profits.
Gladiacoin is essentially a typical ponzi scheme - they don't even attempt to cover it up. Just like MMM though there were tons of advertising, and i wouldn't be surprised at all if the youtubers aforementioned were paid by gladiacoin themselves to do these types of videos.
Sorry to hear that your father's friend got into bitcoin but had such a negative experience. Experienced bitcoiners like us become quite desensitised to new scams because we get used to the constant stream of ponzis. But this one probably made off with 100+ BTC by my estimates.
Watch this YT vid, it's quite helpful:
https://www.youtube.com/watch?v=mHFmp2e3luo
Tracking them down will be possible, however not probable. To run such an elaborate ponzi scheme, they probably prepared rigorously beforehand, and covered their trails with stolen IDs. Even if you do find out who they are, it is likely that they live in a country where law enforcement is not as good.