Chestnut ...
If it's a character in a series then I don't think you should take this seriously. My daughter and I often joke about soap characters and their possible outcomes.... But they are imaginary characters who the script writers have woven a story around, and it all means nothing because they are not real. We don't have any feelings about these imaginary people, including their illnesses, and we don't take the story seriously at all.
I think you'll find that soap and drama writers and actors do an amazing amount of research in order to ensure that they are portraying situations, illnesses etc in a factual and sympathetic way.
I only watch itv soaps, so using only Emmerdale and Coronation Street as my references, in the past few years they've covered dementia, loss of a baby due to genetic issues, cystic fibrosis, downs syndrome, suicide, various cancers and Multiple Sclerosis, and those are only the issues that spring readily to mind.
Anyone who is or has experienced any of the health issues or life experiences that the soaps cover would be up in arms if they "made it all up" as you've implied, the whole point is not only to tell the stories as part of the ongoing shows but also to inform/educate their viewers about those conditions.
Granted, not everyone living with any of the conditions or illnesses portrayed on these shows will experience "exactly" the symptoms shown on the show but these shows do a fantastic job of at least showing "some" of the things people can experience.
I do agree that the characters are fictional and (in the majority of cases) don't actually suffer with the conditions they are showing us but there are real people who watch these shows who do live with these illnesses etc and would perfectly legitimately be offended if they heard someone belittling the character and their situations.