Your Argument:

1) Thoughts require brains,

2) Brains require space and time,

3) Threrefore, thoughts require space and time

4) Therefore, thoughts are not 'outside' space and time

I think you're using the word 'thought' to mean a conscious thought - i.e. the act of thinking. In which case the above argument makes sense. However, I think he was using the word 'thought' to mean the conceptual validity of such ideas in and of themselves. If that sounds too wishy-washy, I offer a thought experiment: What if humans had been seperated into two groups early in evolution (but both groups remained human-like) - Would both groups would have developed advanced mathematics? Would both groups have 'come up' with the mathematical construct of a square? The answer to these questions is probably yes. What if there were 1000 human groups? Again, the answer is probably yes. So the square is 'out there' to be discovered. It isn't a tangible object - the idea of a square isn't made of matter or energy (the brains contemplating squares are, but that's irrelevant).

What if no life had ever evolved anywhere in the universe? Do squares cease to exist? What if there isn't even a universe?

This whole point hinges on whether you consider mathematics to be an invention of man, or a discovery of man.

You didn't have to bother explaining any of that. lol

Yes, concepts are conceptual, not realities.

He may have. I guess I assumed he meant it that way because I've heard it repeated by apologists. "Thoughts aren't material" etc.

I guess I would refer you and him to Sam Harris on 'free will'. Thoughts are pretty well explained.