I've been hit by a bus! Well, a Jeep Cherokee, technically, but I was on a motorcycle so it felt like a bus. I was off work for ~4 months -- couldn't even walk for the first three and could barely feed myself. We managed, though. We got by and didn't have any SHTF moments in my absence.
What happens if I leave, though? I don't know and, TBH, I won't really care; it won't be my problem at that point. How -- if -- things are handed off or transferred off to someone else when I leave will be up to my boss, I suppose.