Patch testing likely wouldn’t have made a difference, this is about extended use that probably broke down her skin’s barrier over time.
When I had a baby and then got COVID, I started washing my hands more often, and really too often. Using the same gentle non scented antibacterial soap I had been for years, I turned my hands into a dry cracked and bleeding mess, and when I used the same gentle non scented oatmeal moisturizer I have used for years, I ended up with insane burning on the backs of my hands, and a bright red burn/rash. This was all in about a week.
I stopped using hot water to wash, and only used soap on my palms/fingers. I waited for my skin to repair itself. Now I continue to use that same soap and lotion with no problem. It was never the products that were the problem, it was over use.
Seems like you mean we, not they