While I’m away, readers give the advice.
On handling a relative who gives your child the creeps:
Standing between any “private” moments between your child and the relative is only one level of protection. You need to give your child another level that’s possible whether you’re there or not – especially if the other parent is not on board, and will see nothing wrong with having the relative and the child watching a movie in the living room by themselves.
Do not point to the relative in any specific way, just make it very clear that you support her right to not be alone with someone who is making her feel weird – in any way. Tell her if she feels uncomfortable being alone with someone, she needs to ask to go talk to (whomever is around), or join them, etc. Give her a variety of options to choose from in how she does that. “I want to call Mom and tell her about the book you got me.” “I want to go to the park” (or wherever other people are around).
Tell her that it is OK to tell people they are really creeping her out/disturbing her/annoying her and she wants them to stop. Now.
I can’t stress it enough: You need to make it OK for her to be creeped out by someone, and support her in taking steps not to be alone with them herself. Give her the tools of how to do that without making it a big issue unless it needs to be. – Anonymous
I left your pronouns intact, but this is an important lesson to teach sons, too, not just daughters. Thanks.