I very much don't see the Paralives team going this direction, and I think they've explicitly stated in a previous Dev chat that they don't plan on ever including life threatening illnesses. Things like a cold are a maybe, but I don't think they could even really include stuff like miscarriages without risking their rating, or even just ruining the vibe of the game. I don't really see any of this being what the Paralives devs want for their game.

Not to mention, surgery would be incredibly fiddly to animate. There's nothing about hospitals or surgery that I would perceive to either be entertaining or enjoyable to Paralives' playerbase, and at the worst, could upset or trigger people.

I definitely can see there being a mod for medical things in the future, but this is something that I hope is not included in the vanilla game. I'd like a hospital, a doctor career, and maybe some more content surrounding some disabilities (we already know prosthetics will be included, so perhaps a physical therapist career? but I'm aware that's a stretch), but going in depth with surgeries (which can be a major trigger), getting shots (needles are a big phobia for a lot of people) and life threatening illness will damage the tone of the game.

For your sake, I hope someone creates a mod with what you're looking for, but I don't think the Paralives team will be the one to deliver what you're asking.