Science is naturalism. It has yet to discover the supernatural. Not wishing to engage in philosophical debate let me say that no proof of the supernatural will ever be found. It's like saying you can enter another reality when in fact it is still your reality. Let's stick to naturalism for science's sake.
Science is not naturalism, naturalism is a philosophical position which claims all phenomena can be explained in terms of natural causes and laws. Science, however is not a philosophical position, or even a conclusion, rather, it is a particular methodology for gaining knowledge.
"Science (from Latin scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe."
The idea that science as a methodology is not equipped to answer questions about the supernatural, or that it will "never" discover proof of the supernatural is a narrow perspective on both the infinitude of reality and the effectiveness and scope of the scientific method itself.
It is paradoxical that on the one hand you ask a question about whether god is real, but then insist on staying strictly within the bounds of naturalism. Yet given the naturalistic limitations imposed by you, the only possible conclusion you can reach is that god is a product of the brain. This is not a scientific attitude, or method, by any definition.
Let's stick to real science and open minded enquiry for truths sake.