In my work I have followed the process of maybe a hundred people dying of various things that we in everyday language sort of collectively call “dying of old age”. Usually there’s a couple of serious conditions underlying, and a general physical frailty. This is anecdotal, but my experience is that people make a conscious effort to get up in the morning and eat food and move around in the ways they can, until they enter a downward spiral where they for example eat less than they should, which means they get tired, they then stay more in bed, leading to less eating, etc. Something relatively minor like a cold, an aching tooth, a fall, a UTI, etc, can accelerate this quickly. Until they have shorter time awake and more time drifting in and out of consciousness, if they are in pain they will get something for the pain, which usually makes them even less responsive. Then eventually the body starts shutting down, they stop urinating etc, and some days later they die.
In this overall process, there’s a time when making an effort to eat and to be active will prolong life, but it seems so easy for them to just… let go, and soon they will be dead. We (the patient + the health care team) usually talk about this at least once, to know what their wishes are. What surprised me in the beginning was that most old people I’ve talked to say that they are done, so for example if the heart stops they don’t want attempts to save them.
All this together, I think old frail people can “hang in there” for a while if they feel motivated, but of course anything can happen at any time anyways.
Have you considered contributing to openstreetmap instead?