Oh, well, whether Fabio wins the last batch of immunities, I really have no idea. So that's certainly not a spoiler, if it came off as one.
I just think that shit with Chase (probably the only guy Fabio thought was his buddy) not picking him to go on that reward like he promised he would seemed to cause him to realize he had nobody to rely on but himself. When a groups gets that cocky in Survivor, to basically all but tell someone their goose is cooked, the person tends to end up with so much more motivation to win, and the hilarity ensues when all the cocky people only have eachother to vote for.
I hope that's how it plays out. And, for Fabio, he'd impress the hell out of the jury given how they essentially wrote him off from the start.