An update…
My mother-in-law has stabilized somewhat, but isn't out of the woods. When I got here yesterday, she was breathing very hard and starting to turn bluish-purple from lack of oxygen in her blood (and this was while she was also on oxygen!). The hospice nurse thought it was probably a matter of hours or a day or two at most. However, after a few hours her color started to improve, and she stabilized during the night. Nobody knows why.
I went home and got a couple of hours' sleep, but my wife was here all night. My brother-in-law is also here from Orange County, so if anything happens both of her kids are here.
And so we continue the watch…