I have 3 kids. A 15 year old son and 8 year old twin daughters. They all get along well and my son loves his sisters and vice versa. Sometimes my husband and I have to go to certain events and I ask my son if he can watch his sisters for the night. He usually says yes unless he has plans (I just ask my mom then).
So on Friday night we had an event to go to and I again asked my son if he’d be willing to babysit. He said sure and that was it. We came back at around midnight and I went to check on the kids and my son was fast asleep, while one of the twins was puking her guts out, and the other one was crying
I was surprised, but I also didn’t really blame my son in any way. They weren’t really making any noise and were clearly asleep before all hell broke loose.