Do you think it’s ok for my bf to tell a guy to stay away from me?

My bf and I work at the same place, same shift. There’s a coworker that has to walk by my work station all day (to go to our front office) and usually once or twice a week he stops and says hi and asks if I want anything from the vending machine while he’s up there. He’s flirty with every girl there..I’ve told him I have a bf and am not interested. I tell my bf all the time when he stops and talks to me and always decline anything from the vending machine. So today I didn’t get any sleep and literally fell asleep at my station..the coworker came over, woke me up and asked again. I asked him to get me a cup of coffee, and I tried to give him the money but he wouldn’t take it. Didn’t think anything of it. Texted me bf right away and told him and he absolutely freaked out. He thinks that because I let him buy me an 80 cent cup of coffee that I showed him I am interested in him?? My bf is telling me that he is going to have a talk with him and ‘put him in his place’ and I think that’s ridiculous. Do you think he is overreacting? I told him to leave it alone and I will talk to the guy but he won’t listen.