Very sad. I suggest you to never put money on small, fake and untrusted exchanges. Only put money in exchange that has a good reputation in the market such as binance, kucoin, bitmex, houbi etc. Our money stay safe in big exchanges. There are many fake exchanges in the market so we should avoid them.
The exchange he was using was the first one on your list of good reputation exchanges. So the instead of saying trust this or that exchange it should be said to trust no exchange and as soon as you can to get your coins into your custody. Glad that you were able to remedy the situation I'm sure that was a very stressful thing to have happen.