Probably lagers, but with most clear beer, the yeast has mostly settled. For homebrew, you can filter the yeast out and force carbonate in a keg system. My question to you is, if you friend has a disease that gets worse from yeast and sugar, why would he want to drink something made out of yeast and sugar??? Welcome to the forum.
Oh, btw, it's not a matter of the amount of yeast in the brewing process - all beer is brewed with as much yeast as the beer can handle. The yeast just propogates itself until the beer is saturated. But after the yeast is done, commercial brewers generally filter the beer to remove the yeast. So Bud, for example, doesn't have any yeast in it. Hefes, on the other hand, are unfiltered and have lots of yeast. That's why they're cloudy.