"there lie the Indian fakir, not dead"
by cm
Hindu Fakir, 1905
Public DomainHindu Fakir, 1905 - Credit: India Illustrated

A fakir is a Muslim or Hindu ascetic.  Denying themselves material comforts, some fakirs are said to possess remarkable powers including levitation and inedia, the ability to live without food.

Van Helsing may be thinking of a famous fakir, Sadhu Haridas, who in 1837 was buried underground for 40 days without food or water.  He survived the experience.