These two poems by Heaney and Thomas both treat death and its impact in a very different way.
Thomas' famous poem, written about the death of his father, captures the determination to fight against the power of death whilst also expressing the fierce refusal of those left behind to accept the death of their loved one. This poem has a very precise and exact structure, using the Villanelle, a notoriously difficult form to master. However, we can see that this form allows Thomas to "cage in" his feelings and emotions and express them in an incredibly powerful way.
The two lines that are repeated throughout the poem express Thomas' attitudes to death: "Do not go gentle into that good night" and "Rage, rage against the dying of the light". In each of these lines, words are contrasted with each other. "Gentle" is contrasted with "rage", "good" with "dying" and "night" with "light". There is also a comparison in tone between the two lines, with the first being subdued and toned down, and the second expressing in full force the anger felt by Thomas at death, enacted by the repetition of the word "rage". The repetition of these lines enforce this treatment of death and likewise these lines are addressed first to the reader and lastly to Thomas' father.
"Mid-Term Break" in comparison is a far more subdued poem, almost conversational in its tone and style. We only realise the theme of death in the poem part way through with the title equally referring to a break from school in the middle of the term as well as the literal "break" (meaning death) of Heaney's brother in his youth. We see how others react to the death of his brother and the speaker of the poem does not talk about his own emotions, rather presenting the reactions of his elders to the death, with his mother who "coughed out angry tearless sighs". The full force of the poem is left to the last line, which expresses the speaker's pain of grief and anger at what has happened to his brother: "A four foot box, a foot for every year."