I'm guessing they're swapping tribes rather than merging, but we'll see.
As for Brandon, at first I thought the entire thing was very put on with the constant threat of ruining the food, then doing it this week, but after the conclusion of the episode, I think he is a very real nutjob.
The fact that Probst had to get him away from his tribe immediately, and try to calm him down, and physically hold him back, and then do the vote on the spot rather than let him have risk more time with his tribe at all before tribal council, I think it was legit. Probst looked genuinely worried like he just needed to get him the hell away from everyone.
I was actually expecting that they might have stuck Brandon on the other tribe, which would have evened it up a bit, and gotten him away from his tribe (although he obviously wanted to go home too), but he was clearly too unstable for that too.
And what a surprise that jock 1 found the idol again.