Full Idea
It seems best to define 'death' in terms of irreversible loss of consciousness itself, since it is from this alone that our interest in the electrical activity of the brain derives.
Gist of Idea
'Death' is best seen as irreversible loss of consciousness, since this is why we care about brain function
Source
Jonathan Glover (Causing Death and Saving Lives [1977], §3.3)
Book Reference
Glover,Jonathan: 'Causing Death and Saving Lives' [Penguin 1982], p.43
A Reaction
I see the point, but this implies no further interest in a loved one who will not regain consciousness. What about subconscious acitivity, or dreamlike states without proper awareness of the external world?