Is there any official method for reading .speccy files on a Mac? If not, how about unofficial ways or a documentation of the file format? My family uses Windows, but I provide the tech support and I use a Mac.
Not that I'm aware of, but you can export the online link and view it from anywhere
Yes, get your relatives to select File and then Publish to Web.
This will provide a unique url link which they can give or send you to allow you to see all their specs.