Bfs sister is weird ab him

This is going to be a weird post but bare w me lol okay so I moved to my new school ab 3 years ago and starting dating my bf 2 years ago well me him and his sister are all the same age and sometimes she will tell me some alarming things for example she once told me that she loved when they got to sleep in the same bed ( I told my bf she said that and now he sleeps on the couch) she also is really thought w him especially when I’m around she will kind of hug him but put her hand right where his pants start I may be over thinking bc I don’t have a sibling near my age but is this normal or...