For the record, the whole channel with the specific encounters is marked as spoilers, there's a seperate one for more vague hints from NPCs and things that have been seen by him directly.
I agree with minimal info being ideal for a natural playthrough, but I think when recording for youtube, it's a bit of a different dynamic for keeping a reasonable pace (both in the video, and IRL workflow because editing takes a while) plus he's not the most observant at the best of times, and commentating makes it quite a lot harder