All - it’s illegal and unethical to discuss in a public forum someone’s health issues by sharing private medical details and making speculations on his health.
It's not illegal to discuss the state of someone's health. Unethical is your opinion. Now if someone was sharing his medical chart, or one of his healthcare providers was disclosing information, that would be a different story.
Nobody has shared "private" medical details. If you read the original post, Peter shared his medical condition with a member of the media.