My DCs stayed the night at inlaws as they have done so on countless occasions. When we arrived to pick them up I was told by my FIL my ds(8) was still in the bath and to go and say hello. The bathroom door was open wide and my MIL was looking in. I thought she was keeping an eye on him. When I looked in the bathroom I saw my niece(19) sat on the toilet laughing and pointing and ds lying on his back (no longer in the bath) with his legs up and apart, spreading himself apart and showing her everything! (sorry TMI)
AIBU to feel very uncomfortable and upset about this? Why didn't MIL tell him to stop or her to get out? she just stood there and watched.
Please don't judge, I'm after ideas on how to gently address this with her as I think it's inappropriate to allow my niece in the bathroom in the first place, she didn't need to be there.