Re: vaccines, unless your husband is taking CAMPATH1a (alemtuzumab) for his MS, there shouldn't be an issue getting HAV/HBV immunization (even then, it's fairly safe, but less likely to be effective), but of course, do talk it over with your physicians. Hep A is a very real risk in China, and there is also a lot of Hep B in the local populace, but as a tourist, you are less likely to be exposed to it. Live typhoid vaccine (not needed if sticking to cities), however, would be a no no on campath.

As others have said, drink bottled water, but do note that good restaurants (the type you are likely to go to), the free water is safe to drink. Foreign branded bottled water is really, really expensive in China, and I just feel ripped off paying for it. As noted, ice in 'fancy' places is safe.

Rest seems to have been covered by others.

tb