How do older people with negligible sex drive manage their health without sex?

Same as young people: Sexual appetite varies tremendously without regard to age. Health is not sex and vice versa. Some feel perfectly healthy without sex and never have it. Witness many religious orders. Some give up sex when older, sometimes due to medical condition and sometimes for a variety of psychologic reasons. Bottom line: health is managed to optimize function. If that includes sex, great. If not, great.