Would you please help me find this book?

The main character (could have been a girl) and a father who traveled to far off places or jungles a lot brought home a wooden crate and inside was a seraph. And it was in the attic or the main character played in the attic. Maybe someone was sick or dying in the hospital throughout the book. At the end something about three interconnected or interwoven rings.

I checked it out from a middle school library in the 1980s. It would’ve been a newer looking book at the time. That’s all I can remember.