She did get eaten, but we never knew what happened to him. They left the house together (with plans to split up and search different areas for food), but that's the last we saw of him.If I remember correctly, the girl got taken down by zombies. The boy saw it, and walked away in a daze.
Yeah, it was Rick's watch. Seeing it, she'd have to know that Sam was one of the victims--I can imagine it made her feel bad, because Rick tried to convince her not to involve those kids with their group at all, and she insisted. If they weren't trying to gather food to take to the prison, they likely would still be alive.