please help

ok, I'm sorry I admit I was trolling people before but I'm actually in need of help this time. My best friend has been talking to this guy from school for just over a week. He is so dodgey and he said he loved her legit like after 1 day. I told her to maybe just steer clear of him because it sounds really sketchy but she didn't listen. I was at her place on the weekend ( he knew I was at her place) and he asked her out OVER SNAPCHAT! Who does that? Then the next day ( I was still there ) and he broke up with her OVER SNAPCHAT AGAIN saying he was confused about the relationship. She was so upset and I told her to stop talking to him. She didn't listen and he asked her out today after school. I need help because I don't want her getting hurt, but I'm also really annoyed that she won't take my advice and ends up getting hurt. I don't like this guy and I don't know what to do to help my friend.