Same question for you:
Can the content of an idea ever be real? Or is it always not real?
I've been trying to make clear: an idea is a mental state (when it is in my head) or a record of another mental state (other than my own) when it is recorded somewhere. In that sense, the idea is real.
But the idea is not the reality -- it is a pointer, like an address register in a computer. It may point to something that is real (in a computer, to an actual address somewhere else in the computer's memory), or to something that is not (in the computer, to an address so high that it does not refer to anything that the computer itself contains).
I can hold in my mind the idea of an Invisible Pink Unicorn -- and while that idea is a real mental state that I can sustain, it does not point to anything outside of my mind that is itself real. I can also hold in my mind the text of a great Shakespeare monologue, and that does indeed point to something real -- I can hand you a page with the speech written on it and you can check whether my mental state contains the speech accurately by listening to me recite it.
I see where you are going, and I don't think you can get there. You are trying to suggest it may be possible that an "idea" exists -- somewhere "out there," all by itself, without any reference to a reality that we can know, or any connection to the mental state of somebody we can question.
I say to you that you can never answer that. The moment you try, it becomes an idea in your own mind -- an instance of your own mental state. And your mental state may, or may not, point to something real outside of that state. But without your mental state, even the idea itself does not exist.