The whole idea that they would put up a two day role playing exercise for the whole camp is kind of silly but to believe that he was crazy the whole time requires WAY too much suspension of disbelief. In the end, Kingsley's intake form on Leo goes on and on about how smart and inventive Leo is which I think was used to explain the Rachel delusion. It makes more sense that that wasn't real; she's running around the island, climbing on those rocks with no shoes? And in the end, there was a real Solando who escaped and they used it to get Teddy on the island at which point they created a fake Solando to... fuck with Teddy?

The beginning also would make no sense. Leo and Ruffalo are basically the only two on the ferry and they don't meet beforehand? He meets his new partner on the boat? And if Ruffalo wasn't his partner, where was his new partner? They just sent him off alone?

And then there's the blood and water from his first visions with his wife, which shouldn't have been there, as well as "Baby, why are you all wet?" which Leo said once and Kinsley somehow knew.

The story is silly as it is but you almost have to be crazy to believe he wasn't.