The short version is that InDesign files are editable in InDesign, not Illustrator. The two of you need to use the same software, and the same software version, for compatibility.
If you've used Illy and Photoshop you might be able to fake your way through small changes to an InDesign file. Download the trial and see for yourself what's involved.
Output the file as a PDF and open that file in Illustrator, There is no going back to indesign after taking it to illy.