Themes are the fundamental and often universal ideas explored in a literary work.  

The Power and Complexity of Love 

The many relationships in They Both Die at the End reveal the power and complexity of love.  Mateo’s love for his parents is tinged with grief since his mother died in childbirth while his father lingers in a coma. His closeness with his father makes it all the more painful that he cannot spend his End Day with him. Similarly, the survivor’s guilt Rufus lives with is the result of his grief for his parents and sister. It is painful for Rufus to live on while the ones he loves are gone from his world. Both boys must also determine how to balance their love for their friends. As much as both Mateo and Rufus want to spend their End Day with their friends, neither wants to force them to endure the loss and pain of seeing their deaths. Mateo initially refuses to tell Lidia he is dying because he loves her too much to cause her further grief in her life. In contrast, Rufus is unable to hide the news from his fellow Plutos, Malcolm and Tagoe, because they are present when he gets the phone call. For Lidia, Malcolm, and Tagoe, not being with their friends until the end is unthinkable. All of them learn that love is worth the pain of loss. 

When Mateo declares his feelings for Rufus, he reveals how love has made him brave. Mateo has spent most of his life avoiding emotional risks, and it is his time with Rufus that allows him to finally risk vulnerability. While Mateo’s End Day phone call prompts him to take action, he is still reticent to take emotional risks until he experiences Rufus’s care and support. Mateo’s declaration of love is also an act of bravery because it is his coming out story. Both the timetable of their relationship and the connection they share gives Mateo the courage he needs to embrace who he truly is. Similarly, Rufus is drawn to Mateo’s kind and genuine nature, which allows him to let his guard down and experience the connection he’s been missing since the death of his parents and his breakup with Aimee. Mateo and Rufus both recognize love’s power to make them better versions of themselves, even as their time on earth runs out. 

The Importance of Living Life to the Fullest 

Both Mateo and Rufus struggle with living the lives they want to have. While Mateo is crippled with anxiety, Rufus battles the anger that comes with his grief. Ironically, it is knowing that they’re dying that frees them both to pursue experiences and explore fulfilling relationships. Mateo grapples with the pain of reconciling the Past Mateo he no longer wants to be and the Future Mateo he’ll never get to be. What he learns on his End Day, however, is the importance of living in the present. He takes huge risks when he leaves his apartment with Rufus, tries dancing and karaoke, rides on Rufus’s bike, kisses Rufus, and tells him he loves him. Similarly, Rufus must learn to accept that the pain of loss is the price for the joy that comes with love. Losing his family makes Rufus drown himself in anger and pain, and that grief prevents him from having a healthy relationship with Aimee. Losing Aimee’s love only increases his anger and self-doubt and snowballs into him making the poor decision to beat Peck up. Being with Mateo, however, makes Rufus realize that regardless of how much time he has, life is more meaningful with love in it. Rufus is finally able to accept that the threat of losing love does not outweigh its importance in leading a full life. 

The Significance of Each and Every Life 

Mateo first introduces the theme of the significance of each and every life as he scrolls CountDowners. Mateo is drawn to the social media app that follows people’s journeys on their End Day because it provides insight into the individual fears and values of total strangers. Mateo believes that every life deserves attention, a philosophy that impacts him in various ways on his End Day. Mateo’s belief that no one’s life, not even an animal’s, lacks importance is demonstrated when he stops in the street to bury a bird. Similarly, the scene where Mateo and Rufus debate the merits of giving a homeless man money reveals Mateo’s unique ability to see all people as worthwhile. Although Mateo has been mugged for his generosity in the past, it has not changed his positive view of humanity. Mateo’s philosophy ultimately saves him from a beating near the climax of the novel when Kendrick recognizes him as the boy who once gave him the shoes off his feet. In contrast, Rufus struggles with the idea that his own life has meaning because of his survivor’s guilt. Rufus questions why he is the only one in his family to survive the car crash, often turning that guilt into self-destructive behaviors. Witnessing and being the recipient of Mateo’s compassion allows Rufus to see himself through Mateo’s eyes as someone worthy of love and happiness.