I don’t know but the idea that our thoughts are identical to electrochemical impulses in the brain is a bit odd too. I am not even sure what it means. Consciousness feels as if it’s a thing in its own right. Dennett says consciousness is a sort of delusion, and all that is really happening is brain patterns. But he’s never made a good answe to Mary Midgley who asks: if consciousness is a delusion, then who exactly is being deluded? If we are capable of delusion about being conscious then there is more to us than just patterns. There is a consciousness that needs to be explained still. And we are back to square one.
In the analogy of the radio I guess we all have our own stations. The important point of the analogy is the brain as a receiver rather than producer of consciousness. How many radio stations there are seems to be a side issue.
Although having said that, some who have explored afterlife stories do describe a sort of collective consciousness, or at least an awareness of consciousness that is not simply clearly individualistic in the afterlife.
Again it somewhat comes down to what you view is fundamental, matter or consciousness. The answer is not straightforward.
The main point is that brain damage does not necessarily prove consciousness can’t exist outside the brain, any more than a broken radio proves a radio station can’t exist outside that particular radio.