Roderick Usher is not well. While parts of his affliction seem to manifest themselves physically, in his overly-acute senses, his illness is primarily a mental one. While his sister is cataleptic and wasting away, Roderick is tormented by, to be quite honest, his own fear. By his own admission, he doesn’t so much fear any particular thing as he fears his own fear. And one day, he predicts, this affliction will kill him.
Which it does, pretty much. One conclusion to be drawn from the final scene is that Roderick dies of fear. Madeline rushes upon him and he falls to the floor a corpse, too terrified to go on living. As we’ll talk about in Madeline’s “Character Analysis,” it’s even possible that Madeline is just a physical embodiment of Roderick’s fears.
But let’s talk about this brother-sister connection. What exactly is going on there? Roderick claims that he and his twin share a special connection, one that others would scarcely understand. As we discuss in the “Sex” section, one interpretation is that they are incestuous. Another, less controversial interpretation is that they share a sort of extra-sensory bond. Those who approach “The Fall of the House of Usher” as a psychological tale posit that Roderick and Madeline are actually two halves of the same person: male/female, mental/physical, worldly/other-worldly, natural/supernatural. See, e.g., Supernatural Horror in Literature by H.P. Lovecraft. If this is true, we can see why Roderick cannot live while Madeline is dead, which explains why she comes back for him. Alternatively, if Roderick may have been intentionally speeding up his own death by burying Madeline early, making her burial something of a suicide attempt.
Another theory involves far less psychology and far more revenge. It’s possible that Roderick knew Madeline was alive when he asked the narrator for help in entombing her. This could be for any number of reasons, and you’re welcome to speculate. (Was he trying to end the Usher line once and forever? Tormented with guilt over the incest they may have committed together? Trying to kill himself by killing his doppelganger other half? (Doppelganger means ghostly double.)) In this scenario, Madeline comes back from the dead to get even with her brother for burying her alive.
We can also think about the spooky connection that Roderick shares with his house. He tells the narrator that he thinks it is sentient or conscious, and that the house is largely responsible for his feeling so dark and gloomy. Many of his artistic compositions revolve around his house (or thinly veiled haunted mansions that act as stand-ins for his own). We know that Roderick is a recluse to the extreme, so his existence is confined by the walls of his house. It might be that Roderick’s very identity has somehow meshed with his house, much the same way his identity might be shared with his sister Madeline. Madeline dies and so Roderick dies, too. Similarly, Roderick falls dead to the ground, and so does his house.
Another oddity to consider here is Roderick’s relationship with the narrator. He doesn’t know this guy that well – they were friends in childhood but haven’t seen each other in years. Roderick reaches out to him for help because he doesn’t have any companions. The fact that he turns to a distant friend is a testament to how very isolated Roderick is. But why reach out in the first place? Roderick knows that he’s going to die (or at least, he’s convinced himself of as much) – so why ask for help? Does he really think the narrator can do anything to help him? Not really, no. It seems more plausible that he invited the narrator as an audience – to watch the horrors that go down between him, his sister, and his house.