I appreciate hearing about this general issue, as I have bunionettes --- little toe side bunions. So not the same, but similar I imagine. My foot doctor told me to either be careful to get wide-toed shoes with enough toe room particularly on the outsides, or get expensive surgery and wait quite a long time before I would be back on my feet. So I've been very careful to always get shoes that work for me.

On the off chance that my dynamics will ever change, I'd be interested to hear how long it takes until she's back on her feet in general, and ready to do significant distance walking in particular. Best of luck to her (and to your Alps hiking in future).