I had to edit your question a bit because we are only allowed to answer one question at a time. The tone of Dylan Thomas' "Don Not Go Gentle into that Good Night" can best be determined by its last stanza. In the last stanza of the poem, we realize that the speaker of the poem is addressing his dying father. The tone here is desperate pleading as the speaker urges his father not "to go gentle into that good night" but to "rage, rage against the dying of the light." We realize that up to this point the speaker has been giving examples of various types of men--wise men, good men, grave men, wild men--all of whom refuse to believe that their lives have reached fulfillment and completion. These examples are all used to persuade the speaker's father that he should continue to fight to live, that he should not passively resign himself to death, that there still is unfinished work to be done.
The tone of the poem throughout is loving, sad, and insistent, becoming more and more intense as the speaker progresses to the end when he directly addresses his father. He deeply wants any emotional response from his father--"curse, bless, me now with your fierce tears, I pray." The speaker refuses to accept the fact that the struggle against death may be too much for the father and demands that the father do more to battle sickness and old age. The speaker is not able to let his father die.