Sorry @Uricon2 just read my last post, I am getting tired, you have probably gone to bed :) I realise I didn't really answer your question. I think in this particular case, the consultant didn't know until some point after the book was published, that the diagnosis had been retrofitted. At the point they did become aware, even if this was when Salray approached them for her rebuttal, they would then have known their 2015 diagnosis had been retrofitted (unless they didn't read the book, or know anything about what had been claimed) At this point they should have realised that Raymoth had profited from this book, which sold largely on the basis of the diagnosis and portrayal of Moth suffering from a terminal condition.
Confidentiality for a patient exists, but if a doctor or consultant is faced with this kind of situation, a patient is not allowed to use a diagnosis in order to profit, they should take advice from their supervisor or regulatory body. It is not a consultants fault, if someone says they have been given a diagnosis of cancer then tries to get money, as you suggest, it's only if the doctor or consultant becomes aware, that they have a duty to report it, to their supervisor or regulatory body.
In straight forward cases of when a clinician should report, for instance, a patient is given a diagnosis of epilepsy and is told not to drive but continues to drive, putting others lives at risk. If the doctor/consultant becomes aware that the patient is still driving, they have to report the patient to DVLA or the police, they can do this with the support of their supervisor or regulatory authority. If they don't and people are hurt the doctor/consultant could be in court explaining why they didn't report them to prevent harm to the public.
In the Raymoth case, the consultant knows his diagnosis has been retrofitted, and that it has been used for profit, he cannot deny that he knows, It is not his fault that Raymoth did that, but when he became aware, whenever it was, he should have gone to his supervisor or regulatory authority to alert them so as not to be implicated.
We don't know if this consultant has now reported the matter, they have allowed the 2015 diagnosis to be posted on Salray's website. I wonder if the consultant in question has thought about why his patient Timothy Walker, who he knows one hundred percent is Moth Winn, didn't tell him about the 630 mile walk, when he was giving his medical history at the first neurological consultation in 2015. Surely he must have thought about this since he became aware of the book and Raymoth's true identity, whenever that was. The fact that the consultant's letters have been shown to the public, now requires answers for the public, otherwise this consultant could be seen as condoning this patient retrofitting their diagnosis for profit.