A director is not required to be a member of the company, unless it is provided for in the company's articles of association. It is normal practice that only members of the management company attend the AGM although any member can appoint a proxy who is not an owner to act as a proxy at the meeting.
When initially formed the management company is usually made up of the developer/ builder and members of their staff or their legal or financial advisors.
There have been cases discussed on AAM previously where the Management Agent is also a director although this may be considered a conflict of interest.
Check the articles of association and if there is no problem there and this director is acting in the best interest of the members, be very happy that someone is happy to give freely of their time to protect other's interests.