I am a single dad who has custody of my 11 year old daughter during the school year. During the summer, however, she stays with her mother in another town. I have become concerned about the lack of bedtime regimen that she has while she's there - she's basically allowed to stay up as late as she wants (I regularly see Instagram posts etc. at 2 AM+ in the morning) on the grounds that "it's summer; she can sleep as late as she wants in the morning."
So - if she goes to bed at 4 AM and sleeps till noon, is there research on whether that's basically as good as 10 PM to 6 AM or whatever? Is an equivalent amount of sleep fine for a kid even if it's not at night? I'm not sure how much of my negative reaction is old-school "early to bed, early to rise" inherited-wisdom stuff vs there being an actual reason that's not good for her. What are the documented effects/pitfalls of "bedtime anytime?"
I have other concerns - a lot of that time is unsupervised, since her mom has young ones they all go to bed early, and a lot of that time is using the Internet... But purely sleep-wise, any thoughts?