How do you return to regular sleep?

Rosie has been sick on and off for weeks. With the latest flu, this past weekend, she took to sleep ping long hours in the daytime then being up late at night, unable to get to sleep p. I am our semi official on call late /middle of the night person, because B turns into a zombie in disrupted sleep conditions, and he was already obviously catching the flu. I adapted by also taking a longer nap in the middle of the day. It feels a little like I'm serving on a submarine, doing short shifts, instead of having normal length days.

Yesterday when I got home from running early evening errands, Brian apologeticaly told me he had kept her awake as long as he could but she was asleep in the Guest room. so I was not surprised when she woke up hungry at 11. I got her ready for bed and fetched her a banana and her meds, including 3 MG of melatonin. I also brought up a fresh batch of library books. She read for a bit, then settled down. I ribbed her feet and legs, which have been hurting. Then I turned off the light. she asked me to sing, so I did. I got back to me own bedroom at 2 am.

How do we get her back to normal?