Shambles....

Here's a likely problem with reversing the strings.

The bridge is usually angled such that the top (high) strings have a shorter length from bridge to nut. The reasons for this are complex, relating to string tension, harmonics, intervals and a lot of other scientific mumbo-jumbo. Needed for proper chording, though.

To make a long story short, It will be harder to tune the guitar, and more difficult when playing chords more than a few frets up the neck (but maybe she doesn't do that anyway).

But, it worked for Libba Cotton, so if she likes it, go for it. Or she could play left-handed AND upside down, like Bill Staines.

I'd recommend resetting the bridge for lefty use - a simple job for a luthier or guitar technician.

Good luck....Tiger