Ah, an original POD!
He died fighting Central Asian nomads, so we can assume he wins ATL. Nomadic tribes being nomadic tribes, any enforced Persian dominion would only work as long as the Persians can enforce it.
After that, I think he'll go after Egypt. He will face a more competent Farao than his son Cambyses II did OTL, but the smart money is still on the Persians here.