don't know of any solution for that one - 6 months is a long time. Not only is the battery going to not be happy, neither are many other things in the car. Engines don't like sitting there doing nothing, all sorts of chemical goings on goes on
find a friend, get them to run the car once a month if possible. Anything you try to do with the battery is a problem - unless you pinch power from the Fluro - which doesn't seem likely. The light from it isn't going to do diddly squat on a solar panel for that purpose.
