Former concert pianist and professional musician here. This waltz is VERY different structurally and harmonically from all of Brent's original stuff that I've heard; which leads me to think it isn't his music.
I'm kind of at the point where I'll just transcribe it from ear and re record this gem for all to use. I just wish I knew who to credit!
thanks for your replies. tried the playlist and got stuck with a a virus/malware/whatever. will try it again, I think I know the R2R means and could correlate it with the playlist. that's when I hit some kind of virus stuff.