If her brain is dead, then what’s regulating her heart and digestive systems? Those things can’t continue without a living brain, or a part thereof. If those autonomic systems can function, then it means there is at least somesb
Give the kid a chance, give her family a chance to absorb it all. A couple of months isn’t going to hurt anything. If her brain CAN do any healing, it tends to happen slowly anyway. There’s obviously some circulation there or else her autonomic nervous system wouldn’t function at all, and it’s functioning.
The Medula oblingota. Her brain will liquify, or already has started to dissolve and will pour out of skull into her sinus' and into her lungs/stomach. Without bloodflow, her body will slowly decompose until her heart finally stops.