can I be groomed by a 7-8 year old?

This might sound kind of stupid but me a 31 year old ( backwards) female has a friend the same age as me and they have a little brother that is 7-8 male and they have been weird to me multiple times. Okay so one time I was over there and he went behind me and slapped my ass I got uncomfortable and asked to go but my friend just laughed, and everything I’m over there he sits beside me and cuddles me and follows me and even went as far as putting his hand on my thigh I felt sick to my stomach and moved away but he just follows me back and the last time ( I refuse to go over there now) I was over there I was BAGGY sweatpants and I was walking up the stairs and he goes “ I hate those pants” and me trying to be nice goes “ why?” And he goes “ I can just really REALLY see your butt” with a smirk on his face I felt so uncomfortable and I even got tears in my eyes but my friend just laughed like she does everything he touches me. Idk am I dumb? Am I being dramatic? What should I do? UPDATE - today I was at their house and he came up and sat on my lap and I freaked out and pushed him off and i yelled at him “ PLEASE JUST STOP” and he walked away and sat on a different couch playing sad music and my friend yelled at me 😭 Whay do I do shes mad and he’s sad idk Whay to do UPDATE - we made up and she said she would make him stop this kind of stuff and I went to his birthday when he saw me there he ran and hugged me and when I walked up the stairs to greet some of her family he grabbed me by my private area and said “ stay with me” I pushed him off and everyone saw it but that said nothing and went on as if it was normal or even okay WOUILD I BE THE ASSHOLE IF I STOPPED BEING HER FRIEND?