Beyond the religious arguments we don't know if the brain exists only in the physical reality in the sense that you can't prove/disprove this hypothesis.
This isn't an explanation. None of it answers the interesting questions.
How and why do computers work? Well they are made of atoms and run on electricity. They do useful work and we call it computation.
This is all true and important to understand, but it is filling a slot that needs to be filled with things like computability theory.
I'm not sure what was meant by nonphysical property, but many materialists disagree over whether consciousness can be copied like a text, or is necessarily destroyed as a book is.
In fact, these are widely debated questions. Materialism is only one of many philosophies that seek to answer these questions (e.g. dualism). Be careful about accepting answers like that if you haven't examined at least the major alternatives.
I may as well argue about how many angels fit on the head of pin—some will find the topic fascinating, but at the end of the day it doesn't actually reveal anything useful about the world.
Are any of these actual debated questions? Outside of religious arguments I don't think anyone can question that (in order) the answers are
It doesn't need a why/It was the best tool our ancestors evolved for their niche
It comes from electrochemical reactions in your brain
Of course it isn't you die when you are killed, getting head injuries can change your personality/memories.
Since your brain exists in physical reality the question "can we run a perfect simulation of physics" is also exactly "can we compute conciousness". Since it's looking pretty good that we can run a simulation of reality at the level we work at it's also looking pretty good for that whole "mind" in a computer thing.