I won't put too much into this source (thanks for posting though) but I said it before and I still believe that Franklin wasn't himself at UFC 64. He looked very pale during his interview on Tuesday (Final Chapter) and didn't look much better come fight night. I don't think he was dying but I don't think he was 100% either.
That doesn't mean Silva wouldn't have won if Franklin was 100% but I think it would have been a much better fight. Hopefully they can work out a rematch and a chance for Franklin to redeem himself.