Only thing we know is that our subjective experience is affected by physical state of the body. How and why - it is still in blackbox.
If you drank, 10 bottles of beer, you will feel drunk and your mind will become happier than you would normally be. And you may even say things you won’t remember next day. Your brain is under the influence, and you will behave and respond in different way than you would in normal state.
If you fall asleep, you won’t be conscious at all. You will be unconscious while in sleep, and be dreaming.
Your physical bodily and brain state will definitely affect your mind, hence we know they are co-related. But how and where in the brain and what cells, neurons or chemicals affect your mind, I don’t know.
We just know any normal human being living and healthy are conscious, because they interact and respond to the world and other humans in natural and intelligible way. That is all we know about consciousness of others.
We only know our own consciousness contents, but never others. Only way we can know others are conscious is how they speak to you, respond to you and what actions they take in daily life situation.
There is no such things the types of conscious state. A person is either conscious or unconcious.
It can be. But that sounds too much assuming with no evidence of being conscious. Someone might be sleeping pretending reading or working on the computer. You only know he is conscious, if he tells you what he is doing or say hello when you said hi.
It was to say, that brain alone or any part of physical body alone is not responsible for emergence of consciousness. Consciousness is not something emerging from brain or neurons on its own. It is not some material or immaterial thing.
Consciousness is non-existent. It is just a word. What exist are the conscious humans and biological beings with the normally functioning living bodies.