I am unsure of where you reside. In my location, areas are divided up into Health Regions. Within each region, the hospitals and facilities are subdivided according to health specialisations. For instance in my city one hospital handles all the maturnity cases, another handles the pediatric care, while another internal medicine and so on. We have three hospitals that everything is split up and assigned accordingly.

it so happens that cancer and palliative care are handled by a different hospital from the one the psychiatric ward is held in. Just a guess here, but the cancer and palliative care was likely deemed to be more of a priority than your friend's mental healthcare and that this was the basis for placing her in the hospital that specialised in that sort of medicine.