Does she have open breaker positions in her box? You could go even lower tech (but just as safe) and move the top RH (2) breakers and put a simple interlock kit in place. They make specific models, for specific breaker panels. They are low tech, and work perfectly every time (and are very easy to install).
All you do to use them is flip the main OFF, then slide up a little metal bar (which was blocking the top two breakers from moving) and engage those top two breakers. The bar will prohibit the movement of the main switch. Once you shut the genset breaker set off, the metal bar will drop, and you can reengage the main upon utility return.
Here is a representative example:
https://www.amazon.com/Generator-Interlock-Siemens-Panel-Murray/dp/B08Y78NVTH
That is not a UL listed product, but a more reputable place like
https://interlockkit.com would have UL and NEC approved items. All just comes down to knowing what panel she has.