Re: Total Desperation...
It appears nobody dares to state the obvious, so I will.
I work with clients that are seriously *not* IT literate, but who need to have basic functionality anyway. Due to circumstances, the use of Microsoft products was not advised in this group.
We switched them all to Apple, for 4 reasons:
1 - decent hardware. Apart from the occasional glitch which you have with any volume manufactured device, we found the kit to work well. In our situation, the fact that everything is soldered in is actually helpful because it makes it impossible to reformat (so theft is pointless, and less risk due to the built-in encryption). That it looks fancy helps too (let's be honest), but fancy and not working isn't going to fly. It depends on context, but the hardware refresh on this project is 4 years and it appears the Apple devices will manage that without too much hassle.
2 - low cost software. For a start, all of them are now on LibreOffice, but that may not work for you (if you go the Linux route you will not have much in the way of options). For the rest, unless you buy specialist software you will not spend much. The most expensive application I've installed so far was OmniPlan Pro for integration with Microsoft Project, but for the rest applications are not only sensibly priced, but also sensibly licensed (Carbon Copy Cloner, for instance, allows multiple machines per license) - I have to caveat here, the app store model differs from the 'external supplier' model. Mixing applications from multiple Apple IDs on one machine is a headache you really want to avoid. In this context, low cost is bizarrely slightly better than no cost because it creates a barrier to too much experimentation. One of the worries I have on Linux is that users start to install stuff like Zenmap and do things they better leave alone :).
3 - usability. With all respect to Linux, the applications are still too focused on users with technical competence. As a matter of fact, I personally think that Microsoft's main hold over the market isn't Excel or Word, but Outlook. Rubbish as it is, there is nothing coming close in integration on any other platform. Usability wins out over any other factor every time because it simply saves a lot of time and hassle. The GIMP is in this context a classic example of an astonishing amount of power let down by an equally astonishingly complex interface. On the Mac you'd install Affinity Designer, Affinity Photo or Pixelmator and actually get things done during the day.
4 - relative security of the platform. Updates generally work, backups are easily made in a multitude of ways including methods that allow bare metal restores, and app store applications get a decent amount of screening. That doesn't represent absolute security (as there is no such thing), but it simply means it takes little effort. This is where modern Linux also works well - user controlled patching is a matter of entering a password.
From a pure cost perspective, Linux is quite simply your best option although you will need to invest some time in making it all work, and easily so. I do think that Apple makes a sensible and safe second option - it did for us.