<<Disclaimer:  Verify this information before applying it to your situation.>>

Dear Eric:

Distilled vinegar is a no-no because it usually is made from grain,
though some is made from wood pulp (yuch!).  Still, I avoid it.  Also
watch out for red wine FLAVORED vinegar, as this is distilled vinegar
flavored with red wine.  If you would like a white vinegar as apposed
to, say, an apple cider vinegar, try rice vinegar, found in the
oriental section of some supermarkets.  Trully 100% guarenteed
gluten-free vinegar would be Balsemic(sp?) vinegar, made in Italy.

Tofu and soybeans should be OK, though some people have problems with
them.  Try out a small amount and see how that goes.  If you're
completely afraid of a bad reaction, avoid it.

If your mother is new to CS, she might want to get a good GF cook
book, such as "The Gluten-free Gormet" by Bette Hagman.  It helps
give you an idea of how to prepare some basic dishes.