Hello Jeanne and welcome.
I am sorry I didn't respond sooner.. When an individual is in end of life stages, their bodily functions slowly begin to close down.
From what loved ones and Hospice explained to me is that the flailing is not abnormal... many patients throw their arms up and down... some of it is from a restless response... were you able to find out more from Hospice?
Please let us know how you and your mom are doing.