There is no supported Progress client available on Mac OS and I doubt that you are able to install any sort of Progress provided ODBC or JDBC driver on Mac OS either.
The most viable option is to use WebServices ( utilizing the Pogress AppServer sitting behind the WSA - Web Service Adapter - running on some JSE ) or using a web browser supported on Mac OS talking to a WebSeed Broker sitting behind some Web Server.
Heavy Regards, RealHeavyDude.