You don't know what you are talking about and you should listen to people who know more than you , instead of pretending you know anything about this.

He said his coin is a Bitcoin fork.
A private key is just a big number. He just need that. A wallet is just an interface that interacts with that big number and generated it.

A wallet address for different coins has just a different encoding and derivation paths, and there are good tools available to use the correct encoding for your coin. For free and trusted. And your "Dev" certainly just used some encoding and derivation paths from other coin.

You can hire someone to do that for you and get scammed again. Or pay big money for someone who will just make that privatekey with a beautiful interface (useless for who understands about blockchain). Or you can do on your own. If you had a different attitude, you would find help here.

Instead of coming with suspicious attitudes and claiming you are rich.