Davi unfortunately only woke up after three months of coma induced slumber. Even if she restarted the experimental procedures, ordering, and collecting the necessary chemicals, items and equipment would take time. Also, there was no way she could jump on it immediately after waking from her coma as she would have to improve on her own health first before she could heal others.
Thus, with all that time limitations, it was already way too late to save Zaki. The hospital had spared no expense – at Sei's instructions – to do their best and fought every step of the way to keep Zaki with them.
However, all their struggles were just them fighting against a losing battle. Without Davi's experimental medication that could be used to treat him, there was no way to reverse the widespread damage that had been dealt to his body, on top of his already deteriorating condition. And to make things worse, just two months after Davi woke up, Juu died too.
