How do you sleep when there is a pregnant woman or a newborn child in the house?

My brother and I live together, his wife is pregnant. She gets up all throughout the night, I can't talk to them about it because I know it's not her choice so that will accomplish nothing and make me seem like a jerk but I keep waking up whenever I hear movement in the hall. Fellow men of reddit, how do y'all sleep through it? How do y'all sleep through an infant waking up in the middle of the night too cause thatll be so much worse.

UPDATE: Thank you everyone who had productive answers, I will be trying some of the noise things, I will also consider melatonin I hadn't thought of that. Y'all are whiskey people eh?