He can use Google's Readium.
I am very new to InDesign and would like to create an e-pub book using ID. My book was created in both .PDF and Microsoft Publishing. Do you know if I'm able to work with these formats using InDesign? Am I able to import the PDF or Publisher file into InDesign?
Now with the latest Adobe Digital Editions you 4.0, you can view your exported ebook in PC with convinience.
Also, With the latest InDesign release you have an option to preview your fixed layout epub using EPUB Interactivity Preview panel which resides in the Window-->Interactive--> EPUB Interactive Preview.
Thanks for the tip Monica, on where to find EPUB Interactivity preview Panel. Video Add interactivity to fixed layout EPUBs | Adobe InDesign CC tutorials shows that it appears under Object > Interactivity. Wow. Glad I can cross that one off my list.