My mother-in-law who lives with us has been diagnosed by the hospice staff as having this disorder. She is constantly needing something day and night. She was prescribed a anti-depressant that is supposed to make her sleep at night, as well as xanax. So far (2 nights) she is resting at night, but when she wakes up during the day she is in constant need of something to make her comfortable. It's absolutely exhausting. They tried her on halidone last week and it worked one night and then for the next few we were up every 30 minutes to an hour. She only takes small sips of water ever so often and only eats about 4 tsps of baby food or pudding each day. We know she doesn't have much time to live, but would like some suggestions.
The other possibility is maybe your mil has pain. I don't know what her breathing is like, but maybe a morphine drip would help.
I think you need to get hospice to do more for your mil. Her final hours should not be filled with dread, fear or anxiety.
Best wishes and my heartfelt sympathy. Cattails.