Parents a & b have specific days they do the night shift dealing with baby. Parent a is on shift but has a cold so comes up with baby earlier (8.30pm) to try and get extra rest, however baby had jabs that day and ended up being very very fussy/clingy, just not herself at all, which meant parent a literally did not sleep until 6 am when parent b took baby. Parent a was then woken at 7 am to start the day. It’s Parent a night again and their cold is worse. Is it unreasonable to expect parent b to take over since parent a is poorly and only slept 1 hr the night before. FYI, neither parent can catch up on sleep during the day.
Yabu - stick to your days no matter what
Yanbu- parent b should step up