I really feel for your mother. I can relate since I have had eczema also called dermatitis since I was a child.
It has come and gone all of my life. It even affects my scalp if I don't treat it.
What I use is our FlakeFree therapeutic lotion, and hair gel. It is formulated with zinc, tea tree oil, and numerous beneficial herbal remedies.
It clears mine up in a day or two. Just have your mother apply it at least twice a day to start with, and then as needed. I would recommend one application after bathing which skin is well hydrated, and then another during the day.
She will see results from FlakeFree or I'll give you your money back including original shipping costs. I am that confident in it's effectiveness.
Plus, it is about a third the cost of anything even close to being like it.
FlakeFree haid gel is also reasonably priced, and there is nothing like it in the world I know of.