Count Dracula is portrayed in the novel using many different supernatural abilities, and is believed to have gained his abilities through dealings with the Devil. Chapter 18 of the novel describes many of the abilities, limitations and weaknesses of vampires and Dracula in particular. Dracula has superhuman strength which, according to Van Helsing, is equivalent to that of 20 strong men. He does not cast a shadow or have a reflection from mirrors. He is immune to conventional means of attack; a sailor tries to stab him in the back with a knife, but the blade goes through his body as though it is air. Why Harker's and Morris' physical attacks are able to harm him in other parts of the book is never explained although it is noteworthy that the failed stabbing by the sailor occurred at night and the successful attacks were during daylight hours. The Count can defy gravity to a certain extent and possesses superhuman agility, able to climb vertical surfaces upside down in a reptilian manner. He can travel onto "unhallowed" ground such as the graves of suicides and those of his victims. He has powerful hypnotic, telepathic and illusionary abilities. He also has the ability to "within limitations" vanish and reappear elsewhere at will. If he knows the path, he can come out from anything or into anything regardless of how close it is bound even if it is fused with fire.  He has amassed cunning and wisdom throughout centuries, and he is unable to die by the mere passing of time alone.  He can command animals such as rats, owls, bats, moths, foxes and wolves. However, his control over these animals is limited, as seen when the party first enters his house in London. Although Dracula is able to summon thousands of rats to swarm and attack the group, Holmwood summons his trio of terriers to do battle with the rats. The dogs prove very efficient rat killers, suggesting they are Manchester terriers trained for that purpose. Terrified by the dogs' onslaught, the rats flee and any control which Dracula had over them is gone.  Dracula can also manipulate the weather and, within his range, is able to direct the elements, such as storms, fog and mist.

Answer this question "how can you kill him" by extracting the answer from the text above.
he is unable to die by the mere passing of time alone.