How long does a Polyjuice transformation last after death?

Question

After reading this answer I found out that the effects of Polyjuice potion persist even after a person dies. Generally, the transformation only lasts for one hour, but in the case of Barty Crouch's mother, she maintains her form for what could be assumed longer than that, since I doubt even Azkaban doesn't have some sort of service after a prisoner dies (i.e. notifying family, preparing the body for burial, having a ceremony, etc.).

“The Dementors are blind. They sensed one healthy, one dying person entering Azkaban. They sensed one healthy, one dying person leaving it. My father smuggled me out, disguised as my mother, in case any prisoners were watching through their doors. ‘My mother died a short while afterwards in Azkaban. She was careful to drink Polyjuice Potion until the end. She was buried under my name, and bearing my appearance. Everyone believed her to be me.”
_{- Harry Potter and the Goblet of Fire, Chapter 35 (Veritaserum)}

While it also appears that the dosage a person drinks can alter how long the potion lasts, I find it unlikely that Barty's mom knew the exact time she was going to die and knew to drink a large portion of potion to cover any chance of it wearing off. So I'm left wondering how she could have maintained her son's appearance so long after her death.

So how long does a Polyjuice transformation last after death?

Answer 1

It’s unclear - at least until Barty Crouch Jr.’s mother was buried.

The only mention of someone taking Polyjuice Potion and them dying before it wore off was in the quote already in the question.

“My mother died a short while afterwards in Azkaban. She was careful to drink Polyjuice Potion until the end. She was buried under my name, and bearing my appearance. Everyone believed her to be me.”
_{^{- Harry Potter and the Goblet of Fire, Chapter 35 (Veritaserum)}}

Sirius saw the burial from inside Azkaban, and saw Barty Crouch Jr. being buried - not his mother. Unlike the Dementors, Sirius wasn’t blind, so he’d certainly notice if the body changed form in the middle of being buried.

“Crouch never came for his son’s body. The Dementors buried him outside the fortress, I watched them do it.”
_{^{- Harry Potter and the Goblet of Fire, Chapter 35 (Padfoot Returns)}}

These quotes show that it lasted at least until she was buried, but we don’t know how long that would have been after her death. We also don’t know if it wore off sometime after she was buried, or if dying makes the body remain in the shape of who it was Polyjuiced to look like.

Answer 2

We don't actually know Azkaban has a service for deceased inmates. I'm thinking of "Count of Monte Cristo" here, for example - dead prisoner put in a sack, then thrown into the sea. That was actually the reality of Dumas's time. For all we know, it could be the same for Azkaban, At least as far as the "jailers put body in a sack" part: they might dig the grave, and have some wizard say a few words over it. Nobody would ever actually get to see who's inside the grave.

In saying "I doubt even Azkaban doesn't have some sort of service after a prisoner dies", you're assuming our modern societal norms. But our modern societal norms also don't go about shutting inmates in a deliberate pit of despair - we focus on rehab instead, right? (I mean - in theory. No comment about practice - not getting into politics. Thing is, the dementors and what they did was very much an integral part of the system.) We would consider Azkaban on par with the worst tales of Guantanamo. Can we make any assumptions about such a place?