My previous post doesn't actually comment on the chapter, so here goes.
This is a very heavy thing for Josh to learn about, the possibility that this version of him may stop existing. Regardless of what his foggy self says, he needed for some people to know this to have them as emotional support. Plus, while I'm not saying foggy Josh is evil, his interests are probably not fully aligned with the post crash Josh. That foggy guy seems to have some kind of purpose as part of a mission, with his actions and opinions probably being based on that goal. Meanwhile, our Josh just wants to be able to live a regular life and get to explore the normal things about the world that he only remembers when he sees them. And not because of regular amnesia, his lack of memory is clearly caused by this whole weird dynamic on his head, maybe to keep some information safe by even himself not knowing it.