According to the bestiary
"A humanoid who dies of ghoul fever rises as a ghoul at the next midnight."
By RAW, a humanoid infected with ghoul fever but finished off by some other means (natural or unnatural) does NOT rise as a ghoul, correct ?
So an NPC slowly dying of ghoul fever in a cage hopes to die of starvation first so that he doesn't rise as a ghoul (since he lacks the means to commit suicide).
And a BBEG who wishes to help the ghoulification along has to be careful to only stab him enough to ALMOST kill him.
Its always possible to chew through your own wrists , but if said prisoner isn't determines enough or is shackled to the wall.
A character can go without water for 1 day plus a number of hours equal to his Constitution score. After this time, the character must make a Constitution check each hour (DC 10, +1 for each previous check) or take 1d6 points of nonlethal damage. Characters that take an amount of nonlethal damage equal to their total hit points begin to take lethal damage instead.
Disease (Su) Ghoul Fever: Bite—injury; save Fort DC 13; onset 1 day; frequency 1/day; effect 1d3 Con and 1d3 Dex damage; cure 2 consecutive saves. The save DC is Charisma-based. A humanoid who dies of ghoul fever rises as a ghoul at the next midnight. A humanoid who becomes a ghoul in this way retains none of the abilities it possessed in life. It is not under the control of any other ghouls, but it hungers for the flesh of the living and behaves like a normal ghoul in all respects. A humanoid of 4 Hit Dice or more rises as a ghast.
So yes, thirst should kill you before the ghoul fever does, unless for some reason you have a lot of hit points but lack the constitution to make two dc 13 fort saves.
According to the bestiary
"A humanoid who dies of ghoul fever rises as a ghoul at the next midnight."
By RAW, a humanoid infected with ghoul fever but finished off by some other means (natural or unnatural) does NOT rise as a ghoul, correct ?
So an NPC slowly dying of ghoul fever in a cage hopes to die of starvation first so that he doesn't rise as a ghoul (since he lacks the means to commit suicide).
And a BBEG who wishes to help the ghoulification along has to be careful to only stab him enough to ALMOST kill him.
I'd say that's up for interpretation. Ghoul fever can cause Con damage.
For example, if say a humanoid has a Con 10 prior to getting Ghoul Fever, yet Ghoul Fever reduces Con to 7. It makes it much easier for the humanoid to reach the Dying stage. And Ghoul Fever causes the humanoid to die at HP - 7 instead of HP -10. So without Ghoul Fever, in this example, the humanoid may not be dead. Primary Cause of Death: Stabbing; Secondary Cause of Death: Ghoul Fever.