At least the meta-objective was achieved, and your sister-in-law did learn an important lesson, albeit one on built-in obsolescence and the importance of open file-formats, rather than on the subject the professor was a professor of.

Presumably the university has student computer rooms available, well-stocked with PCs running the right version of Microsoft Office? Or perhaps "a PC with Office 2003 installed" was specified in the course-requirements document she was sent? If neither of those apply, then IMO the professor should be reminded that it's not fair to require his students to use specific proprietary software, let alone specific versions of software whose version upgrades are charged-for.

Peter