What do I do about this guy?

Basically there's a guy i've been friends with for about 4 years and most of that time he had a girlfriend but about 6 months ago they broke up. He's a great guy but I've never seen him as anything more than just a friend. Anyway a few months after they broke up he asked me out and i turned him down. He was upset for about a week then got over it and we were back to being friends like before. Recently he's been more flirty and even our mutual friends keep bringing him up to me and telling me to give him a chance. Everyone keeps asking me why i won't go on a date with him and idk what to tell them, i just don't feel anything/fancy him but they still keep on! He keeps messaging me hinting he wants to take me on a date and idk what to do, I've already said no before and i don't want to offend him but like wtf do i do about him and our friends, i have no interest in the guy and never will

Just tell him he reminds you of your brother, he'll get the message