Answer:
It reinforces the idea that all people, not just the speaker's father, should fight against death.
Step-by-step explanation:
"Do Not Go Gentle Into That Good Night" is a poem by Dylan Thomas first published in 1952. One of the theme of the poem is death. The speaker is witnessing the death of his father, revealed in the last stanza of the poem. He recognizes in his poem, the nature of death, which is unstoppable. In first five stanzas of the poem, the speaker tells how every kind of person will face death.
So, the speaker is not only telling his father not to give in so passively to death, but also other men.