Help me stop my FIL getting scammed urgent!

Hi all

I’m right now scrambling to stop my father in law from getting scammed by an investment firm trading bitcoin. It is Finex Ltd.

He has transferred around € 10.000 by now and is promised to have a payout of more than € 100K. There seems to be a 100K balance in USDT in a coinbase wallet on the solana network but it seems to be locked. And from wHAT i understand, solana does not support USDT.

Finex is now asking him to deposit another € 10K to withdraw the money. I am absolutely convinced he is getting scammed and I am trying to keep him from paying more.

Can someone explain how this scam works so I can convince my FIL?

🙏 Thank you!!