Misunderstanding may arise by confusing the Buddhist and scientific definitions of death. Within the scientific system you spoke quite validly of the death of the brain and the death of heart. Different parts of the body can die separately. However, in the Buddhist system, the word death is not used in that way. You'd never speak of the death of a particular part of the body, but rather of the death of an entire person. When people say that a certain person died, we don't ask, "Well, which part died?"
Be it known that Men of dull faculties and slight wisdom, They who cling proudly to signs, Cannot believe in this Dharma. Now I, joyfully and fearlessly, In the midst of the bodhisattvas Frankly casting aside my expedient devices, Merely preach the Unexcelled Path.
Cut down the forest, not just a tree. Out of the forest of desire springs danger. By cutting down both the forest of desire and the brushwood of longing, be rid of the forest, bhikkhus.
The Buddhist tenet, "Non-killing is supreme virtue", is very good, but in trying to enforce it upon all by legislation without paying any heed to the capacities of the people at large, Buddhism has brought ruin upon India.
Let go the past, let go the future, and let go the present (front, back, middle). Crossing to the farther shore of existence, with mind released everywhere, do not further undergo birth and decay.
The poisonous serpent of afflictions is sleeping in your mind; just as if a black viper were asleep in your room. You must use the hook of precepts to quickly remove it. When the sleeping snake is gone, then you can rest at ease.
Therefore, be ye lamps unto yourselves, be ye a refuge to yourselves. Hold fast to the truth as a lamp; hold fast as a refuge to the truth. Look not for refuge to anyone besides yourselves.
When ever Buddhism has taken root in a new land, there has been a certain variation in the style in which it is observed. The Buddha himself taught differently according to the place, the occasion and the situation of those who were listening to him.
A family is a place where minds come in contact with one another. If these minds love one another the home will be as beautiful as a flower garden. But if these minds get out of harmony with one another it is like a storm that plays havoc with the garden.
I myself feel, and also tell other Buddhists that the question of Nirvana will come later.
There is not much hurry.
If in day to day life you lead a good life, honesty, with love,
with compassion, with less selfishness,
then automatically it will lead to Nirvana.