Is it against the law for a childs bed to be set up in a hallway?

A friend of mine is beside themselves because of this issue. His ex wife recently found a 1 bdrm place that she and her 5 year old daughter share. She moved her boyfriend in with her, and in doing so, decided it was acceptable to set up the 5 year old's bed in the hallway, making it her sleeping area while she and the boyfriend take the bedroom, Is this legal? The bathroom is only a few steps away, I have been unsuccessful in finding any laws for this in California. The child has shelter, food, clothing. The issue is the sleeping arrangement.