I think single focus AF could work well. I mean, they still need to know HOW to use focus.
If they don't need to film themselves (vlogging-style), then as @Grimor mentioned, a used G85 (what they are called in the US of A, guess in Japan they are the G81), could work great. AF-S is trustworthy.
They will need to know about lighting though, and M43 sensors do like having a lot of an appropriate amount of light.
I see them go for about $450 to $475 used on a popular website.
The panasonic 30mm f/2.8 macro is currently selling new for $300.
If she is going to be filming herself and will be moving around in the frame, or basically needs AF-C, then a used Olympus E-M1 MK II is a good camera with reliable continuous autofocus (if it is an MSC lens) and very nice straight-out-of-camera colors.
Hope this helps.