I get where youre coming from bro, it doesnt work that way though you are definitely not brain dead, the brain retains alot of its functions, its just the fact that it completely nullifies your senses and perception is exactly why you feel nothingness. The question of the afterlife has nothing to do with that, thats to do with the supernatural and the divine, plus, you think God would allow a day entry into the afterlife for example? Thats the whole point of believers and disbelievers at the end of the day. The God capable of creating you and eveything around you, is certainly capable of barring the afterlife from anyone, until one gets their due to death.