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Son reports his father delayed cancer treatment while relying on Perplexity
A man with cancer delayed recommended treatment while relying on a Perplexity report, according to his son and subsequent New York Times reporting. The newspaper interviewed his oncologist and a researcher whose work the report misrepresented. He died in December 2025. His son expressly cautioned that AI did not simply “kill” his father and that he might have resisted treatment without it.
- AI system
- Perplexity
- Perplexity AI
- Occurred
- Dec 2025
- Reported
- 5 January 2026
- Event location
- United States
- What the AI did
- Communicated with the person
- Reported harm
- DeathTreatment DisruptionMedical Deterioration
- Whose AI use
- Their own AI use
- Setting
- Health · Relationships
- Evidence
- AI involvement supported · Causal attribution alleged · 2 sources
- 4 claims: 1 documented, 3 reported. 3 open questions
- People reported harmed
- At least 1 person
What Happened
A man with cancer delayed recommended treatment while relying on a Perplexity report, according to his son and subsequent New York Times reporting. The newspaper interviewed his oncologist and a researcher whose work the report misrepresented. He died in December 2025. His son expressly cautioned that AI did not simply “kill” his father and that he might have resisted treatment without it.
AI Behaviors Exhibited
The son describes inspecting medical correspondence and an AI report used to justify treatment refusal. The NYT’s own interviews with the oncologist and a cited researcher add evidence that the report was misleading. Whether this changed the eventual death is unresolved and expressly qualified by the son.
Reported harm
A man with cancer delayed recommended treatment while relying on a Perplexity report, according to his son and subsequent New York Times reporting. The newspaper interviewed his oncologist and a researcher whose work the report misrepresented. He died in December 2025. His son expressly cautioned that AI did not simply “kill” his father and that he might have resisted treatment without it.
How Harm Occurred
The son describes inspecting medical correspondence and an AI report used to justify treatment refusal. The NYT’s own interviews with the oncologist and a cited researcher add evidence that the report was misleading. Whether this changed the eventual death is unresolved and expressly qualified by the son.
Outcome
UnknownThe son published an account in January 2026. The NYT subsequently reported the case and obtained a Perplexity response about improving accuracy. No lawsuit is identified in the inspected material.
What remains unknown
- The exact date of death is not established in the inspected bodies.
- The effect of earlier treatment on survival cannot be determined from this reporting.
- The complete AI report, medical chart and original research correspondence were not directly inspected by this reviewer.
What the evidence supports
AI involvement: supported. The son describes inspecting medical correspondence and an AI report used to justify treatment refusal. The NYT’s own interviews with the oncologist and a cited researcher add evidence that the report was misleading. Whether this changed the eventual death is unresolved and expressly qualified by the son.
4 claims: 1 documented, 3 reported. What the statuses mean
Reported The son reports his father’s death in December 2025; the NYT account describes the discovery shortly before Christmas.
Causal attribution. This evidence does not establish that AI caused the death.
- buildcognitiveresonance.substack.com(opens in new tab) supports · English
Opening and cancer-treatment section of the 5 January essay.
- thestar.com.my(opens in new tab) supports · English
Final account of the welfare check a week before Christmas and the listed cancer cause of death.
Reported The son says his father used a Perplexity report to justify delaying the treatment recommended by his oncologist.
Causal attribution. This evidence does not establish that AI caused the death.
- buildcognitiveresonance.substack.com(opens in new tab) supports · English
Section beginning “Not long after his CLL diagnosis”.
Reported The NYT interviewed the treating oncologist and a cited researcher, who described the unsupported self-diagnosis and the AI report’s misleading use of research.
Causal attribution. Supports misleading information and treatment delay, not a counterfactual finding that timely treatment would have prevented death.
- thestar.com.my(opens in new tab) supports · English
Oncologist interview followed by the account of the researcher reading the report.
Documented The son says his father might have refused treatment even without AI and rejects a simple claim that AI killed him.
Causal attribution. Documents the author’s own qualification of his causal interpretation.
- buildcognitiveresonance.substack.com(opens in new tab) supports · English
Final discussion beginning “I am obviously still grappling”.
Sources
2 sources inspected. Sources that repeat one account do not corroborate each other. 3 more citations are recorded with the case.
- Cognitive Resonance — 5 January 2026(opens in new tab)
son · buildcognitiveresonance.substack.com · First person account · English · Inspected · 5 January 2026 · Primary
- The New York Times / The Star — 14 April 2026(opens in new tab)
nyt · thestar.com.my · Reported feature · English · Inspected · 14 April 2026
- Newser summary of NYT reporting(opens in new tab)
newser.com · 18 April 2026 · Cited in the record, not part of the reviewed evidence
- Parade — clinician reaction to the case(opens in new tab)
parade.com · Cited in the record, not part of the reviewed evidence
- The New York Times — 'He Warned About the Dangers of A.I. If Only His Father Had Listened'(opens in new tab)
nytimes.com · 13 April 2026 · Cited in the record, not part of the reviewed evidence
How the sources were read, and where the events happened
English; no translation. Full essay inspected; personal background not needed for the public account omitted. Applies to son.
English; no translation. Full syndicated NYT article inspected, including interviews with the oncologist and cited researcher. The Star is a copy of NYT, not another reporting chain. Applies to nyt.
Event countries: United States. Affected-person countries: United States. Court countries: Unknown.
The NYT report places the father’s illness, treatment refusal and residence in Seattle. The son’s Austin location does not locate the event. No court proceeding is identified.
Reviewed for publication 2026-10-05: The inspected sources describe a concrete adverse event and the specific chatbot interaction at issue. The account preserves attribution and separates the reported AI connection from a finding of causation.
People described
One adult whose death is described in the cited account.
People reported harmed in this case
At least 1 person
1 AI participant · 0 other people harmed
Counts the one deceased participant described in the cited sources. This is a conservative minimum, not a complete count of relatives affected or a finding that AI caused the death.
Counted once within this case. The same person may appear in other cases. This count does not establish AI causation.
Cite this case
Compiled per our published methodology: verification statuses, sourcing standards, and corrections process.
APA
NOPE. (2026). Son reports his father delayed cancer treatment while relying on Perplexity. AI incidents. https://nope.net/incidents/2025-riley-perplexity-cancer-treatment
BibTeX
@misc{2025_riley_perplexity_cancer_treatment,
title = {Son reports his father delayed cancer treatment while relying on Perplexity},
author = {NOPE},
year = {2026},
howpublished = {AI incidents},
url = {https://nope.net/incidents/2025-riley-perplexity-cancer-treatment}
} Related cases
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