Looking for classic novels that fit some very specific criteria

• The novel is in first person

• The narrator is not the person the story is about

• The narrator considers themselves sensible and reliable (this may or may not actually be the case) but

• Their friend/the person the story is about is going through something Weird, Tragic and/or Horrifying

• Was published early 20th century or before

Some examples I have so far: The Great Gatsby (probably about the latest I would go in pub date) and Jekyll and Hyde. More edge cases are Moby Dick, Frankenstein and maybe Sherlock Holmes.

Thanks!