Complex sentence: Gus and Wes are characters is Joseph Heller's novel Catch-22, they are assistants to Doc Daneeka, who take the responsibility for dealing the majority of people who visit the medical tent.
Split into simpler sentences: Gus and Wes are characters in Joseph Heller's novel Catch-22. They assist Doc Daneeka, who takes the responsibility for dealing with the majority of people who visit the medical tent.