I may take some heat for Jenna, but if you know Mom is that sick, why even agree to go?
In Jenna's defense, it's always hard to tell with aging and ailing relatives, who can be declining for years,
and survive several crises, before taking a sudden turn for the worse. In the meantime, life goes on and you can't put your entire life on hold because a loved one is going to pass away at some unknown point in the future.
I know that I've personally rushed across country at least twice because an ailing relation appeared to be at death's door, only to have them rally and live for several more years--until the next crisis, or the next. And I used to work as an orderly at a nursing home and, trust me, sometimes the final descent can come on very quickly and without warning. A resident could seem fine in September and be gone by December . . .
It may well be that Jenna's mom's health appeared to be stabilized at the time she volunteered for the show, only to take a sudden turn for the worse at the wrong time.