Looks like something illegal then it's probably wise for me to not get involved.
There are many legal tax loopholes. Don't go cod the illegal ones. Find an island where corporation tax isn't a thing. And then one where income tax isn't a thing...
I don't think it's illegal, I've had a guy that owns a company that does these types of exchanges vet him and he says the guy is legitimate. The problem now is the guys company wants to take the cash to their bank and deposit it which will take 2-14 hours and then send the BTC and the investor wants the BTC right after the cash has been counted and verified. Seems like a reasonable thing to be concerned about