The big question is, if Google has an API so you can directly retrieve Google docs and import them through one of the solutions mentioned in that forum post into eZ. This would require quite some eZ and coding knowledge. I'd first check out those links, see if they bring you any further to a solution.
Regards Robin
Board member, eZ Publish Community Project Board - Member of the share.ez.no team - Key values: Openness and Innovation.