He’s not the first one to ‘kill his liver’ with paracetamol/ acetominophen (tylenol). First case I recall, the person was taking tylenol nightly with a glass of wine. Here’s some links on the current understanding of Liver injury and paracetamol:

Apparently it’s not always overdosing: Paracetamol-induced hepatotoxicity at recommended dosage (https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2796.2003.01097.x)

Acetaminophen-Induced Hepatotoxicity: a Comprehensive Update (https://pmc.ncbi.nlm.nih.gov/articles/PMC4913076/) “…in the United States, in particular, it accounts for more than 50% of overdose-related acute liver failure and approximately 20% of the liver transplant cases.”

Risk Factors for Hepatotoxicity Due to Paracetamol Overdose in Adults (https://www.mdpi.com/1648-9144/57/8/752) “In the univariable analysis, significant hepatotoxicity risk factors were male gender, alcohol abuse, an ingested paracetamol dose, and a timespan from ingestion to hospital admission. The later one was the only significant risk factor in the multivariable model (adjusted odds ratio 1.08; 95% CI: 1.03–1.12).”

Paracetamol (acetaminophen) overdose and hepatotoxicity: mechanism, treatment, prevention measures, and estimates of burden of disease (https://pubmed.ncbi.nlm.nih.gov/37436926/) “Where data were available, we estimate that paracetamol is involved in 6% of poisonings, 56% of severe acute liver injury and acute liver failure, and 7% of drug-induced liver injury.”

Understanding paracetamol-induced liver failure (https://link.springer.com/article/10.1007/s00134-014-3293-9)