I’ll throw out a good reason one wouldn’t want to share cancer type. Cancer types vary heavily in prognoses, but they also vary heavily in prognosis within a certain type and heavily varies on the individuals own body and health. Say he has a bad cancer type and stage, but his doctor gave him a pretty good prognosis based on his specific circumstances. People just associate with the cancer type and the public, people you don’t know, just start spreading garbage like damn you’re probably going to die and you feel terrible and hopeless and not what you need in the middle of a cancer treatment. The less you reveal, the more you protect yourself from armchair doctors causing you insane amounts of stress and anxiety; all of which are terrible for the body.