The concepts of disease and cure are part of our medical systems. Disease is not well defined. Cure is less well defined. It is also important to understand that if or when a single case of a disease is found, by Joe and Jane Smoe, to be cured, it does not mean that "the disease" is cured. Only the single case was cured.
A case of disease is cured by addressing its present cause. For example, we can cure many specific infectious diseases caused by a bacterial infection, a fungal infection, or a viral infection by surgically removing the infected tissue, or by a specific medicine that kills or disables the infectious agent. This is the standard definition of cure in today's medical systems. However, the "disease" is not cured, only the specific case. Every infection might be caused by one (or more) infectious agents - and different cures will work on different infections that might appear similar. Every cause of a disease (infectious or not) might be addressed by many different curative actions.
Diseases like "influenza" "arthritis" and "cancer" consist of a wide variety of individual cases, each with individual causes. Even when a case has a single cause, it still has many potential cures.
Joe and Jane might find cures. That's not difficult. Most illnesses are minor, and easily cured. Proving the cure (of a case of any non-infectious disease) is simply impossible in the current medical paradigm. It gets worse. It is not even possible to prove that a case of infectious disease was cured by a non-approved treatment. The test for cured, in modern medicine, requires either a clinical study - not just a single case, or an approved medicine. Doctors can claim that a non-approved treatment caused a cure. Nobody cares. It cannot be officially recognized, much less proven without general definitions of cured and cured by. Today, we simply do not have such a definition. Most cures cannot be recognized. No doctor, medical clinic, hospital, medical system, or insurance system counts cures. Treatments are billed. Cures are not billed.
Sharing information about the cure that has been found is not a problem. Sharing a book about the cure is possible, but the publisher might insist on a standard disclaimer like "this book is not intended to cure any disease." Sharing an unapproved cure product is generally considered illegal. It is not legal, for example, to market (probably not even to give away) Vitamin C supplements with the intention to CURE any disease. No medical reference text prescribes Vitamin C as a "cure" for scurvy, it is documented as a "treatment." There are claims, for example, that high doses of Vitamin C, over a period of a few weeks will cure many cases of hypertension - high blood pressure. But, the treatment is not approved, and hypertension cured is not medically defined.
For example, Hopkin's Medicine advises, "Doctors don't know what causes psoriatic arthritis. But factors such as immunity, genes, and the environment may play a role."
Proving a cure requires proof that the cause has been successfully addressed. It thus requires agreement on the cause in the specific case. Modern medicine generally ignores specific cases.
When a case of disease like psoriatic arthritis rash is cured - it's easy for the medical system to assume that the diagnosis was wrong, and move on. Doctors often respond with statements like "I don't know what you are doing, but keep doing it." It's much more difficult to study and understand, much less promote or share the cure. Individual doctors can and often do find many specific cures in their own practice and experience, but sharing them could lead to accusations of quackery (at best) or a threat to their license to practice medicine, or even legal action.
Note: that my original answer to this question was flagged as "that looks like spam." I do not know the cause of that flag, but I simply removed some content and it passed. I stated above, talking about cure "could lead to accusations of quackery" - or of spam.