Final answer:
In 'How I Live Now,' Joe dies from blood poisoning caused by a rusty nail, while Major McEvoy is killed by enemy forces during the war, though his death is not directly depicted.
Step-by-step explanation:
In the novel How I Live Now by Meg Rosoff, the characters Joe and Major McEvoy meet their end in quite tragic circumstances. Joe, the youngest of the cousins, dies as a result of a blood poisoning after stepping on a rusty nail. Despite Daisy's attempts to treat his wound, they are unable to get proper medical help in time due to the war, and he succumbs to the infection.
Major McEvoy, who is Daisy and Piper's great-uncle and the owner of the farm where they are staying, dies off-screen. Readers learn about his death indirectly; he is killed by enemy forces while away from the farm, as the war's hostilities reach their area.