Reggie's death as an allegory
Not to reduce Reggie's death to mere metaphor, but the reader does notice in the novel that as the reader is facing Ptolemy's death with a sense of mystery, Ptolemy is facing Reggie's death in kind. So there's a sense in which death is death, universally, so Ptolemy facing Reggie's murder is the same as him coming to terms with the fact that his long, long life is coming to a swift, terrifying end.
Ptolemy Grey as a universal image of death
Ptolemy is not just dying, he has dementia. He recalls a particularly painful event when he decides to cut off his friendships, because he can tell by their eyes that he has stopped making sense. Alone, he has faced his death for years, understanding clearly that his understanding itself is slipping away. He will be left to face his death from a position of absolute horror with a mind that can barely fathom else, or he can go out with a fight. He picks action.
The motif of help
Ptolemy Grey is a group project. He's human and he's limited, so he depends on others. Once in the character of Reggie, once in the character of Robyn, but mostly, he depends on the help of doctors who can give him clarity, but who cannot give him time. There is a limitation to how we are permitted to help each other.
The death motif
There are multiple deaths in the narrative, and the formation of a motif is crucial to understanding the plot, because all the deaths must be seen as the same death occurring in different ways. That's important because the novel is designed to give the reader the impression that secretly, the novel is about the reader's death, not this fake Ptolemy person.
Mystery and horror motifs
There are designs in the novel's plot that clearly indicate the novelist borrowing from mystery novels and thriller novels to create a sense of astonishment, surprise, drama, and ultimately horror. The book acts as an apocalyptic story predicting not the death of Ptolemy, but the death of everything and everyone. Not exactly a happy story, but it is a meaningful and powerful story.
