Please speak to your hospice nurses, they will know best as they have seen this many, many times. My father was in similar state as your mother, however he had been vomiting for weeks before j tube placement. His oncologist said 4-6 weeks remained. However, the hospice nurse assessed him that same day and recognized he was not tolerating the feedings and could see the decline daily. She told me my father had more like 4-6 days. He found eternal peace 10 days later.