Palliative care is what is sometimes administered to those with a terminal illness, over a period of time usually. Are you suggesting that Madeleine was secretly whisked away because she was terminally ill and taken somewhere unknown to be looked after by persons unknown in her dying days?
That would be a narrow meaning of the word.
https://en.wikipedia.org/wiki/Palliative_care "Palliative care is provided by a team of physicians, nurses, physiotherapists, occupational therapists and other health professionals who work together with the primary care physician and referred specialists and other hospital or hospice staff to provide additional support.
It is appropriate at any age and at any stage in a serious illness and can be provided as the main goal of care or along with curative treatment. Although it is an important part of end-of-life care, it is not limited to that stage. Palliative care can be provided across multiple settings including in hospitals, at home, as part of community palliative care programs, and in skilled nursing facilities. Interdisciplinary palliative care teams work with people and their families to clarify goals of care and provide symptom management, psycho-social, and spiritual support."
