Not to chastise you or your wife, there is an actual "Liver Warning" on Tylenol Product labels. They warn against 4000mg/day or with alcohol consumption. It's not an on/off switch, the damage occurs on a ramp that achieves a critical point after so much consumption.
Saying this to encourage label reading and to refute those who might try to characterize your wife's experience as anecdotal. And for those who stop reading a page like this one, after the first paragraph that touts "no evidence": https://www.tylenolprofessional.com/safety-and-efficacy/safe... when at the bottom it reveals the Liver Warning.
>or with alcohol consumption
This part is what a lot of people miss IME
It appears his wife took under that threshold and only for a few days. 4000mg is roughly 8-10 otc painkillers in a day (depending on the brand).
That said, everyone's physical ability to metabolise drugs is different. I might worry something else was wrong, or at least get a followup test done later, if her liver tox screen showed that, just to rule out another cause.