Even if it is a minimal chance the brain can have function then the patient can be consider alive supported with medications and machines.
The person will be in vegetable state but still alive. Even in this state of living the body will die. There some cases where in vegetable state it does not require breading support for the body and person is leaving for some amount of time. According to Beernet in his six elements “… death must be an event and not a process”. Exactly, a sudden experience, if is a process then it is requires time and support. “Death is the irreversible and permanent loss of the critical functions of the organism as a whole”. If is consider the patient is with irreversible brain death, then it goes under several different test to determinate the brain death, and then the body is under withdraw care and/or including hospice, which means the organs will start failing until all the organs stop working and will become a sudden death of the whole
body.