Hello, the "live" and "dead" in "some people are alive" and "some people are dead" are what biology and medicine call life and death.
"He is dead" means that it is meaningless, "He is still alive" means that his spirit is still praised by others
The meaning of that paragraph is: Although alive, he is still dead. Life has no value. The latter sentence refers to those who serve the people throughout their lives and are willing to be the people's servants. Although such people no longer exist, their thoughts and spirits will remain in the world forever.