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

The coincidence of MS and CD in 2 sibs of one family may be just that a
coincidence in a family possibly with a predisposition to autoimmune
disturbances.  There is however the other possibilty that is that the MS
patient sufferes from a neurologic complication of undiagnosef CD.
about 5% of CD
patients get nerve damage that can vary from tingling and numbness in the
feet to confusion, memory loss, dizziness and loss of balance, visual
abnormalities.  Thes sometimes happen in the absence of GI symptoms.  Any
sibling of a person with celiac disease should be screened for celiac
disease. it's a long shot that neurological problems would be due to a
covert case of CD but IT should be checked none the less.
This is not specific medical advice. joe murray