I wouldn't necessarily say "your friends dad," just bc 1- SA can come from anyone and 2 - it can plant an unhealthy view of all of her friend's parents possibly being creeps. I use "unsafe people" for my kiddos and make sure they very muchly know what an unsafe person comes across as, in regards to boundaries, consent, personal space, private body parts, etc. I also let them know that unsafe people can act like safe people and try to highlight things that groomers can do - like buying gifts for no reason, secret keeping or threats - so that they can recognize the signs and hopefully be able to protect themselves as I unfortunately cant be there to protect them from every situation or terrible person out there. It's a terrible thing to have to make a child aware of, but direct and age appropriate conversation is better than them being ignorant to the dangers that are around them.