You shouldn't dismiss your sibling's complaints.
Leah is sharing a room with her brother for the night and wants the window open for fresh air, but her brother wants it closed because of his allergies.
Leah wants to get a good night's sleep.
Leah leaves the window closed out of consideration for her brother since closing it doesn't harm her.
Leah waits until her brother falls asleep and opens the window and leaves it open for the rest of the night.
Leah and her brother are both able to sleep through the night without any problems.
Leah's brother wakes up with a headache and sore throat because the open window triggered his allergies.