Wow it is not common for people to acquire Hep C through sex. It can happen though but it is rare. My husband and I had sex for 9 years and I didn't acquire it. Though his was non-dectectable when I met him.
Have his doctor refer him to a GI or better yet a hepatologist once you get the viral load back like Connie suggested.
Take care.........thoughts and prayers............
When the going gets tough....the tough get going! Don't always know where I going but I get there anyways.