Unless it affects you, I don't think you should speculate.
I've lost a lot of family members to Cancer and worked in end of life care. There are similar themes, which each persons Cancer, but there can be large variations.
No-one believed my DH was ever as ill as we said, because he carried on working and 'bounced back' after each period of ill health, he went on to take himself to hospital, 'not feeling right' and died, pain free, weeks later, we knew that the Cancer had spread everywhere.
If I explained the 5 years build up (and when I have talked about it), I haven't been completely believed.
It was very hurtful that this came from Collegues, Friends and even Family members.
I've got Lupus, most people don't understand having a lack of immunity and I've been questioned quite aggressively on occasion.
There's been times, when I've had hospital appointments and I haven't been well enough to take in the information, I've known my Consultants for seven years, I trust them, so I haven't questioned everything, I've just hoped I'm feeling well enough on my next monthly appointment.
Most people haven't had low hemoglobin, low immunity and illness, so don't understand why you might be unquestioning and vague and assume you're lying.
I do know a person with Munchausens, hers is a need for attention by Professionals, she was in Foster Care from the age of 18 months. She is somewhat indulged by HCPs, because in her case, she is at risk of self harming/endangering herself.