@dandelion_3000 I think the best thing you can do is to just busy yourself with something else. Maybe if there are fun things to do on campus, do that. Or see if there are any cool places near campus.
Or maybe just focus on your studies. My mother always says that if you're busy, you don't have time to stress about things.
I'm not saying that you'll forget about him by distracting yourself, but it can help.
And this friend of his? Keep a close eye on him, bestie. Because he did something like that, you need to watch out for him.