I don't know why, but I feel as though the son wasn't planned, and Sam and this woman became a couple to raise the child because they liked each other well enough. I think circumstances of which there could be many that prevented a sibling -- everything from fertility issues to actual health maternal problems. We see her only once as a blurry figure in the background, which says so much, but I think she may have died when the son was relatively young. That may be why we don't see her again. She is a complete mystery. How did Sam meet her? Was she a hunter? A woman he saved from a monster? Maybe a librarian in a random town? I kind of like that idea, and the sad pink dress would certainly work with that. LOL

That is so sad about your friend. Grief is so powerful.