Nick,
If anyone knows how to handle old Macs it's you. But, I think most genealogy programs now read and write a common interchange data file, like the CVS tables used today.
If the same was true in the past (don't know when it started) he may be able to export it from the old Mac and mail it to himself to read into a new genealogy program.
Hey that's great if 15 year-old genealogy files can be read/imported by more modern applications...certainly not something that can be done with many 15 year-old files!
That would then leave only one hurdle...how to import the info from 3.5" floppies (if they're still readable after 15 years, since degradation can happen)...into a more modern computer.
The ideal setup is to have about a 12 year-old Macintosh computer that still has a floppy drive...and has USB capabilities (via a USB expansion card). Then a USB "thumb drive" can be used to transfer the data.
Networking via ethernet is also a good way to transfer the files...unfortunately...a Powerbook 180 does not have ethernet. And there can sometimes be some complications "ethernetting" an old Mac running OS9 & a more modern Mac running OS X (10.4, 10.5, 10.6...I haven't tried to do it in a while).
Like I mentioned earlier...getting data from 3.5" floppies into a more modern computer is more difficult than you would think.
- Nick