under hospice care

My little girl ,well I should say i call her our little one that never grew up, she is 18 but weighs 42lbs, 46 inches long, never walked, signs and is our joy and love. hospice tell us her pulse is thready and blood pressure is dropping with low sats. her stoold have gone from yellow now topea green and soft/diarrhea. does anyone have any idea what is causing this and is this just the process we are dealing with?