I went back to look at my review for this book because I also did not like the way Bree was with Archer.

1. She called him her "silent boy" or something like that throughout the book and it just sounded gross to me, especially since she never actually calls him that to his face(iirc) but only in her thoughts.
2. When he leaves without her and she says "how is he communicating in the world" like she literally had a deaf father she knows people who can't speak are able to function in the world. This definitely helps your point that she saw him as almost childlike.