FireDAC driver API is not documented. In any case it is a complex task, which is ~ 2 months for develoment and ~2-4 months to make the driver really stable.
Instead you should consider to use a custom mtier client, which will deliver data to the client and will populate TFDMemTable. Other option - consider to use new RAD Studio RESTfull API.
-- With best regards, Dmitry Arefiev / FireDAC Architect