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Why not have a look at tucows [tucows.com] and do a search for WYSIWYG. Try out a couple of different programs yourself and suggest your favourite.
You also have the option of downloading the 30 day trial version of Dreamweaver MX, if you're family enjoy creating the pages they might even go out and buy a copy.
Personally I use 1st Page 2000 from Evrsoft - also free.
I developed a couple of PPT slide shows that helped, placed them on their desktops so they could refer to it when needed.