Did Barty Crouch Jr. have a terminal illness?

Question

NominSim makes an excellent case that Barty Crouch Jr. was already dying while in prison at Azkaban in his answer to this question.

“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)

Seems that some terminal illness was slowly killing him over 11 years. (11 years is the amount of time he was free after escaping from Azkaban.) Or maybe he only had months to live and then recovered since a prisoner would be denied medical care, while somebody outside a prison could get such medical care. (e.g. - If a lifelong prisoner and a law abiding citizen both need a lung transplant to live and there is only one donor lung available, which one deserves the lung?)

What malady, if any, was slowly killing him?

Answer 1

Probably not - it seemed to be just the effect of being in Azkaban.

It seems most likely that it was the effect of being in Azkaban. Sirius told Harry that Barty Crouch Jr. died in Azkaban, and that many others did as well. He also said Barty Crouch Jr. looked sickly when he arrived in Azkaban, but whether that was due to a separate illness is never mentioned.

“No,’ said Sirius dully. ‘No, he’s not in there any more. He died about a year after they brought him in.’

“He died?’

‘He wasn’t the only one,’ said Sirius bitterly. ‘Most go mad in there, and plenty stop eating in the end. They lose the will to live. You could always tell when a death was coming, because the Dementors could sense it, they got excited. That boy looked pretty sickly when he arrived.”
_{^{- Harry Potter and the Goblet of Fire, Chapter 27 (Padfoot Returns)}}

During a portion of the time while Sirius would have thought Barty Crouch Jr. was in Azkaban, it was actually his mother taking Polyjuice Potion. However, on the first day he was brought in, he certainly wouldn’t have been switched out for his mother, and he seemed to be already affected by being in Azkaban. In addition, he said Winky had nursed him back to health, which wouldn’t be possible if he had a preexisting illness that would be terminal in the wizarding world.

“The house-elf nursed me back to health. Then I had to be concealed. I had to be controlled. My father had to use a number of spells to subdue me. When I had recovered my strength, I thought only of finding my master … of returning to his service.”
_{^{- Harry Potter and the Goblet of Fire, Chapter 27 (Padfoot Returns)}}

Barty Crouch Jr. seems to have healed fully after being taken care of, which wouldn’t be possible if he was dying of a terminal illness. From this, we also know it wasn’t just the effect of taking his mother’s form, since then he wouldn’t need to be nursed back to health. He’d just immediately become healthy again when the Polyjuice Potion wore off.

It seems the most logical conclusion that being in Azkaban was sapping his strength and will to live, and would have been deadly for Barty Crouch Jr. had he stayed. Some people survived being in Azkaban (like Bellatrix, who was imprisoned there for fourteen years and wasn’t sickly when she got out), but many people died from its effects on them. Sirius said Barty Crouch Jr. looked sickly when he came in and started screaming for his mother by the first night - he didn’t seem to be the sort that could survive Azkaban. Once he got out, he escaped the conditions that were killing him, and with care from Winky, he was restored to good health. The “illness” caused by being in Azkaban was cured.

Answer 2

Being in Azkaban is a terminal illness.

In spite of opposition from many wizards, among them experts on both Dementors and buildings with Azkaban’s kind of Dark history, Rowle carried out his plan and soon a steady trickle of prisoners had been placed there. None ever emerged. If they were not mad and dangerous before being placed in Azkaban, they swiftly became so.

It was only when Diggory went to visit that he realised exactly what conditions inside were like. Prisoners were mostly insane and a graveyard had been established to accommodate those that died of despair.

Back in London, Diggory established a committee to explore alternatives to Azkaban, or at least to remove the Dementors as guards. Experts explained to him that the only reason the Dementors were (mostly) confined to the island was that they were being provided with a constant supply of souls on which to feed. If deprived of prisoners, they were likely to abandon the prison and head for the mainland.

_{Azkaban by J.K. Rowling}

I would hazard that Barty Jr. had been in Azkaban so long that he was succumbing to the fate that all of prisoners who entered fell to.

Answer 3

No, Barty Crouch Junior wasn't dying.

There's no indication that Barty Crouch Junior was dying at all.

The reason the Dementors viewed Crouch as a "dying person" was because of the Polyjuice Potion.

"They came to visit me. They gave me a draught of the Polyjuice Potion, containing one of my mother's hairs. She took a draught of Polyjuice Potion, containing one of my hairs. We took on each other's appearance."
_{(Goblet of Fire, Chapter 35, Veritaserum).}

I disagree with NominSim's theory that Barty Crouch Junior was already dying. It makes no sense for his parents to engage in a daring and highly risky escape attempt if they believed that he was already dying. Their endeavour would have been futile if Crouch Junior's death was imminent.

The only person who was "dying" was Crouch's mother. When Crouch Junior took the Polyjuice Potion he took on his mother's physical form - including her illness. As far as the Dementors were concerned Crouch Junior was "dying" because he had taken the form of the body of a dying woman. They detected one dying person (Mrs Crouch) entering and the same dying person (or so they thought) leaving. The whole statement about a dying person leaving is told from the Dementors' point of view, which is incomplete because they are blind. It isn't intended to tell us anything about Crouch Junior himself.

We know that people who take Polyjuice Potion take on the deformities and disabilities of their targets. Thus Crouch Junior's leg shrunk to become Moody's stump and Hermione inherited Harry's bad vision.

"Harry, your eyesight really is awful," said Hermione, as she put on glasses.
_{(Deathly Hallows, Chapter 4, The Seven Potters).}

In the same way, Crouch took on his mother's illness when he took on her body. When the Polyjuice Potion wore off he no longer had that illness.

It's not the right place for me to fully answer the linked question. But I would prefer David Stratton's answer, which says that Mrs Crouch died because of the limitations of the Polyjuice Potion. In other words, if you're dying when you take the Potion you will still be dying, even if you're taking possession of a healthy person's body. Otherwise Polyjuice Potion would be a means of cheating death or achieving immortality, if the old and the frail permanently steal the form of the young and the virile. I think that it's fair to assume that the healthy can (temporarily) assume the form of the dying but that the dying cannot regain their health by taking the form of the healthy.