It's fairly easy to create an eBook. First, if you haven't already, download and install Calibre. It's a free eBook database application that will sync with your eReader as well as convert HTML, PDF and eBook formats from one to another.
Then, develop your eBook in Microsoft Word (or OpenOffice Writer if that's your preference). If you're looking toward the Kindle file format, follow the instructions from Amazon at the links in this thread for formatting so it will appear properly. When you save it, save it as an HTML file.
Finally, add the HTML file to Calibre, then use Calibre to convert it to the ebook format of choice (for your intention to go Kindle, that would be Mobi). If you want, you may want to delete the HTML file after your eBook has been created, but you don't have to. Calibre will show both formats.
He could of course buy the Atlantis word processor which outputs epub natively and then run titles through Sigil to add the table of contents.
Then you only need calibre to convert to mobi and you have an ePub ready for all the non amazon stores.