That sounds very subjective, we know the brain houses memories, certain parts do certain things. We know a color, a sight, a sound, if something is hot or cold because of sense data being received from impulses to the brain. I believe in the immortal soul but like a lot of people I believe God created both the mind and reality, God gave us the ability to perceive reality as it actually is.
Now don't get it twisted, I'm not saying that the brain is the source of consciousness.
What I would say here is that it seems in your words to imply that the brain is not a construct of consciousness. It's a typical thought, but one which I reject since, there is no way to falsify "not a construct of consciousness": do you know what I mean? Even if (not that you are but if) a man says "the brain is the source of consciousness" I would ask for evidence that the brain itself is not a construct of consciousness. I would again state that, through dreams/imaginings/etc. I know that a "reality" can exist which is completely constructed of consciousness. If I were dreaming of a brain, the brain itself would be a construct of consciousness; thus there is no need of a "not constructed by consciousness" thing even in the "waking world" in order to construct an experienced environment. So to one claiming "There is a reality which is not constructed by consciousness" I would reply "This is both unecessary to explain reality, and also unfalsifiable; therefore rejected, and all of reality is constructed via consciousness" and following this line, there must be a singular consciousness which constructs all of reality: i.e. God.
That said, you mention dreams, you seem to think are illusions and you could make that argument.
Let me note that "illusion" carries a connotation of "not real"; but I'm not saying everything is "illusion" but that everything is construct of consciousness, and that dream environment is every bit as real as the waking world environment: both are of the same "creative substance": the only discernible difference is that the waking world seems to be constructed in a more "rigidly cohesive" manner
I can think of no other source for dreams then the subconscious. We really don't know where they come from exactly but not all of your brain is part of your consciousness. You put your hand on something hot, your hand jerks back, you didn't consciously make that happen. It's called the Limbic system, it felt the heat and just pulled back your hand as a reflex action, your physical brain over ruled you conscious mind. We did this little exercise when I was in the Army, the SF guys can in and had us walk in a circle, then one of them would fire a starter pistol, everyone ducked. They said that is the Limbic system and if you can control your breathing...etc, you can control that reaction.
Okay, but here you use the phrase "physical brain" and I have to ask for specificity: are you meaning a "brain" that is not constructed by consciousness? Are you implying that the "physical" is
not a construct of consciousness? This is as if you and I are in a dream, and there is a brain on a table, and you motion at it saying "the physical brain": I would reply "What you call 'physical' is a construct of mind; there is no "brain not constructed by consciousness"
There are also problems you run into with say, Schizophrenia. Research is telling us that it's actually related to genetic mutations working in concert with various other processes. This person may hear voices, might be able to think he is somewhere else or believe something that is not real. That's part of the reason so many of them end up on the streets, in their minds, they are somewhere else. It's defective brain function.
Again, you're coming from a point of view that there are things that are "not construct of consciousness": my objection is still, such a notion is both unnecessary to explain reality, and scientifically unfalsifiable. A "not constructed by consciousness" reality is no different than proposes elves in a hypothesis: neither are necessary (Occam's razored away) and neither are falsifiable (unable to be scientifically/philosophically valuable)
A person who is hearing voices is really hearing voices, and the voices are real. If you hear a voice in a dream, you are really hearing a voice, and the voice is real. If you are flying in a dream, you are really flying: the experiences are all as real as any other thing that is experienced. If a person is "somewhere else" in their mind, then they really are somewhere else in their mind. To you, they really are not; to them, they really are. What we experience is what we are really experiencing. The only alternative is to hypothesize a "not constructed by consciousness" waking world, but again, this hypothesis is both unnecessary and unfalsifiable.
Accordingly, seeing that our senses sometimes deceive us, I was willing to suppose that there existed nothing really such as they presented to us; And because some men err in reasoning, and fall into Paralogisms, even on the simplest matters of Geometry, I, convinced that I was as open to error as any other, rejected as false all the reasonings I had hitherto taken for Demonstrations; And finally, when I considered that the very same thoughts (presentations) which we experience when awake may also be experienced when we are asleep, while there is at that time not one of them true, I supposed that all the objects (presentations) that had ever entered into my mind when awake, had in them no more truth than the illusions of my dreams. But immediately upon this I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be something; And as I observed that this truth, I think, therefore I am,[c] was so certain and of such evidence that no ground of doubt, however extravagant, could be alleged by the Sceptics capable of shaking it, I concluded that I might, without scruple, accept it as the first principle of the philosophy of which I was in search. (Descartes's 1637 Discourse on the Method)
What Descartes is saying is similar, but his proverbial lens is reversed. He is setting out to "disbelieve" all that he can disbelieve as "not real" and ended up with the only "certain reality" which cannot be disbelieved as "false": cogito ergo sum; I think therefore I am. But I'm saying the opposite: nothing can be disbelieved because everything experienced is "real"; whereas Descartes is presuming a "reality not constructed by consciousness" which is "real" and all else "illusion"; I am saying that, everything experienced is really experienced, and no different in the quality of being "real" than any other thing experienced. In short, that which is real is that which is really experienced. Descartes differentiates between "dream world" and "waking world" as though the one is a product purely of mind, and the other is not. I would object on the same grounds: Descartes cannot "prove" a the waking world experience is any different in creative substance than the dreaming world; and since we know by self experience that "not of mind construct" is unnecessary to create an environment, then his unstated proposition that such a "not of mind" construct exists is both unnecessary and unfalsifiable. That being the case, only a construct of pure consciousness is available, and, known through conscious experience of the experiencer.
So, in the end, again: all of reality is a construct of consciousness, and taken as a whole this is the product of a singular consciousness. Thus, ultimately, there is One Consciousness from by and through which all of reality is emergent.