You can do it!! If you don't, all you're ever going to think is what if I had done this or that. Even if he chooses not to accept the apology (which I think he wouldn't do if you say you guys were as close as you once were) at least YOU got closure knowing that YOU did the right thing. Maybe even after you apologize he'll still be a bit standoffish but I know when I'm mad at someone and they apologize it still takes a little bit more for me to come around because I don't want to just go from mad to best friends again (even if I REALLY do, I'm just stubborn hehe)