I’m the oldest of 12. I was 13 when my baby sister Tess slept in my room. I was responsible for changing and feeding her in the middle of the night (she was 6 months plus…I don’t remember exactly). That was pretty much the beginning. (To be fair, she was one of two babies who was passed off so young, but still.)
My second sister (seven years younger than me) is mother to our second-youngest sister, Abby. I don’t say second mother. I say mother. After a high-risk pregnancy, mom had an emergency C-section, and Abby became Beth’s buddy. She couldn’t nurse, so she was purely bottle-fed. Beth did everything for her. Last I knew, Abby would come to Beth if she had a problem, before she would come to mom.
Beth and I shared a room for many years, and the younger girls’ room was right next door. When Tess had nightmares and hallucinations, most likely it was Beth or me (or both) who got up with her. When the little girls needed help going to the bathroom in the middle of the night, it was us again who helped (or the twins, when they got older).
It wasn’t that our parents’ room was across the house, either. It was across the hall from our rooms. They believed they deserved the right to sleep through the night while someone else took care of their kids. They believed they earned the right to sleep through the night while someone else took care of their kids.
Child labor laws would rule that out for unrelated children, but within the family it’s ok to make children do the night duty.