The experts cannot know the level of mental functioning by a CAT scan.
BTW, The "experts" talked down to the courts and the public by saying the brain "liquified." In fact, those cells which died were removed by white blood cells and resorbed by the blood flow to the areas that were functioning. The cerebrospinal fluid increased to fill any voids.
"Letting her go" is not the same as deliberately going to the hospital to remove the tube and while forbidding food and water by "natural means." That is the definition of intervention to kill.
This happens all the time when it comes to these sort of cases.