catatonia

my sister has catatonia following severe depression. she suffered nms in the early stages of her treatment. she has been catatonic for 15 months, with occasional lucid spells. she is unable to eat or drink except when lucid, and is medicated and nourished via a gastro peg. she cannot walk or stand,due to the catatonia and footdrop (a complcation of the nms) she rarely talks, is doubley incontinent and unable to manage her personal hygiene, in short the only thing she does for herself is breathe. she was initially prescribed olanzapine, fluoxatine and lorazepam. then quetiapine and lorazepam. she is currently taking clozapine and venlafaxine. she has also had 33 ect sessions which were stopped several months ago. she has been to the national hospital for neurology and neurosurgery in london and undergone extensive testing namely ct, mri and pet scans. also several eeg scans and a lumberpunch. no physical cause can be found. we are at our wits end and would welcome any suggestions for further treatment, investigation, or assistance. please help!