The world, indeed, is like a dream and the treasures of the world are an alluring mirage! Like the apparent distances in a picture, things have no reality in themselves, but they are like heat haze.
There is a way to be purified, to overcome sorrows and grief, to release suffering, to secure the right path to realize nirvana. This is to be mindful.
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?"
All things appear and disappear because of the concurrence of causes and conditions. Nothing ever exists entirely alone; everything is in relation to everything else.
Do not believe in anything simply because you have heard it. But after observation and analysis, when you find that anything agrees with reason and is conducive to the good and benefit of one and all, then accept it and live up to it.
Imagine a multidimensiona l spider's web in the early morning covered with dew drops. And every dew drop contains the reflection of all the other dew drops. And, in each reflected dew drop, the reflections of all the other dew drops in that reflection. And so ad infinitum. That is the Buddhist conception of the universe in an image.
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.
If you resort to violent methods because the other side has destroyed your monastery, for example, you then have lost not only your monastery, but also your special Buddhist practices of detachment, love, and compassion.
Spend 5 minutes breathing in, cherishing yourself; and, breathing out cherishing others. If you think about people you have difficulty cherishing, extend your cherishing to them anyway.