Just joining with my contribution to the never-ending truth that people are weird! But starting off with my best friend, who died from a brain tumour despite exhaustive treatment. The cancer had wide-ranging effects both physically and mentally, as did the treatment; I doubt anyone could fake it convincingly.
I have a now-distanced friend with a "very aggressive stage 4" cancer that very definitely wasn't. She may have had an early-diagnosed cancer successfully treated, I don't know. A few years later, though, it became apparent that she was developing Alzheimer's. She could've misinterpreted her early symptoms and even treatment due to muddled cognition.
Far more spectacularly, I was socially involved for a while with an absolute raging narcissist, who was incredibly entertaining but dangerous to the unwary. She had a brain tumour, ovarian and vaginal cancer, heart disease and a bunch of other things. Throughout it all she was energetic, charming, beautiful and grasping. All her diseases were terminal but she eschewed traditional medicine, spending tens of thousands of other people's money on spiritual healers and holistic treatments. She could've made a fortune putting her manipulative charms to legitimate use but, evidently, preferred grifting.
Then there was Gilly at work, who very obviously had anorexia but chose to present as suffering an unspecified cancer that she had for the whole four years I knew her. She had regular hospital appointments, returning to work the same or next day, and only took homeopathic medicines. She cropped up on my LinkedIn recently, having worked up until retirement (so she's been healthier than me!)
The insides of other people's heads are nothing if not interesting 😏
Taking a moment to think of friends Meghan, Steve, Jackie and Paul, whose glioblastomas killed them 💔🌹