Dani -- I wish I had brilliant words of wisdom but ...

Best I can do is to suggest this mom most certainly seek more opinions re
treatment of this problem.  You don't mention whether other members of family
have -- perhaps it is not genetic?  Surely if it is environmental then a
causative agent can be isolated.
How about a pediatric allergist??  She needs to find a physician who shares
your attitude -- we have a problem so now let's go find a solution.

Has she changed detergents to one of those no-perfume types?  Tried soap
flake type?  Stopped using softener?

My son had a MILD tendency to eczema -- nothing compared to the situation you
describe -- brought on when I ate tomatoes or, later, when he ate tomato
sauce.  Dairy may have been an issue.

Good luck.
Joanna Koch, IBCLC in Los Altos, CA