This is often a fabric-of-space problem. The fracture doesn't cause the proximate death. Instead, the fracture and the death are both effects of a deeper cause: the whole body is wearing out. Sometimes you see a warning injury or two before the system collapses. Other times you see what's called a cascade failure, when a whole bunch of stuff wears out at roughly the same time. These are actually rather well known features of old age, but people really don't like to talk about them, because folks tend to go apeshit if you point out that a break means it's a good idea to brush up end-of-life plans.
But there it is. Bodies wear out. If you know the signs, then you can respond accordingly. Is the person done with their lifework? If not, either finish it quickly or look for ways to buy a little more time. They might have more, but don't count on that. Do they have a care plan, will, etc? If not, make those now. Think very carefully about stances on life-sustaining treatment. You need to distinguish whether it's just an ordinary fracture (i.e. other health is fine and life still busy) or the beginning of the end (especially if other health is declining and life is mostly or all wrapped up). Fighting to prolong life in a falling-apart body is a miserable disaster for everyone but the people who make money from it. A graceful exit is both more dignified and less unpleasant. If one doesn't know how to disengage, try talking to a clergy person; some of them are trained for that. Some sacred texts have instructions too, if one prefers reading to talking.
Everyone dies sometime of something. Watch for the signs so nobody misses their exit, because that sucks.