So what if I remake it before he patents it? Is my implementation then prior art?
If you're right, the patent system is yet again more broken then I thought.
No, he has 1 year from public disclosure to file for a patent (in the US, as of 2006 when I took my IP law class [IANAL, btw]). You could not file for a patent because his public disclosure would count as prior art for you, unless you could prove that you had the idea before his publication.
You are right. You cannot patent something that has already been published elsewhere.