I think Alma Jr. knew. I won't try to convince anyone else to agree with me, thought I know many do, but many don't and that's OK too. One of the beautiful things about this movie/story is that so many people come away with so many differing opinions about what the what, the why, the who, the how. Fascinating! Anyway, for me, growing up with five siblings in a small house, there was not much we didn't know about each other. Certainly, I have never been a mystery to my family. People who know you, know you.
Jim