Update on Mom is that she was able to come off the ventilator for quite a few hours yesterday but had to go back on during the night because her oxygen level had fallen to the mid 80's (normal is 95-100). They've sedated her again since she's back on the vent.
Dad talked to the doctor who is coordinating her care a couple minutes ago. The doctor told Dad that they probably just tried a little too early. They'll leave her on there a couple more days or so and give it another shot.