Is a medical condition not PII? Together with the fact that it's linked to a specific person, their tasks, responsibilities, mannerisms. Even an IP address is PII, not sure how a full chat log isn't, even if it's not text-book PII.
PII is not a thing under the GDPR. Like, at all. Personal data is. Personal data and PII are not the same thing.
Isn't any personal data a PII? You just need a couple of personal o enable t identify individual. And if this is in an org then amount of individuals is quite small, so sometimes it needs just one personal detail.
Read Article 4. "PII" is not a thing in the GDPR.
If you have dyslexia and I know it, that brings it down to 20% of people. Combined with some other data, this is a pretty good factor to narrow it down to "who you are", right?