Would you want to meet your child’s bf/gf before they stay the night ?

This is for parents of teens. I’m not a parent of a teen yet but my brother in law is a teen and he’s had his gf stay the night for the past 3 days now. His mom is a live in nurse so she’s un aware… I’m not tryna be disrespectful to his mom by not saying anything but it’s not my business to tell. I’m thinking maybe I can get him to tell her so I don’t feel like I’m betraying his mom in a way… Ps I have no problem minding my business I just feel bad and idk why..