It's a much needed rest. (Though I gotta wonder if aside from the exhaustion of tending to a corpse getting to him it's also because of Seishin's attitude letting him down, again)

I also like that Seishin having his ugly side revealed to Toshio doesn't stop him from doing things he's most comfortable and suited doing. I think he's pretty ashamed since Toshio really rubbed it onto his face about what kind of person he actually is, but even if Toshio's expectation has been restricting him, Seishin is putting a limit to that, and it's in a way good for him (even if it's not good for the villagers). He's rather highly conscious about image, so I'm kinda afraid. Part of it is probably because of Sunako's 'influence' tho.

Generally though, even if he's been restricted by Toshio's expectation just like he's been with his parents' and the villagers' overall, I think he overall has a healthier relationship with Toshio in that he's not actually that afraid to act as himself compared with other villagers and his parents. He also isn't just blindly following Toshio's commands or anything -- he isn't Toshio's puppet, like you said. He instead asserts his opinions a lot when he thinks he's right about them, and some in turn make Toshio reflect on them. He's just as active in their relationship just like Toshio is, and he can be as influential to Toshio just like how Toshio is influential to him. If he works to meet Toshio's expectations, part of it is because he truly wants to, both for Toshio (helping him) and the villagers (though a bigger part of his heart probably wants to screw it all). If they weren't born in Sotoba, or if they weren't born an Ozaki or Muroi, I think their relationship could even be healthier and better. I have lots of respect for their relationship, considering they're two opposite people and they could come this far.