I they are/ were good mates, at least try! When things blew up with my ex (were incredibly close friends, similar situation to you when we initially broke up) it all went horribly wrong, i acted like a c.unt and so did she, i gave her a full on apology with a general "this is my last try, after this it's your call" theme to it and then she didnt speak to me for 6 months, felt so shit every day from then until she phoned me a few days ago to say sorry and i've felt f**king awesome since! Leaving things in a good place is always gonna be a good thing to do.
Let them sober up, give the one who's your age old fiend call if no one else and try. If it doesnt work, leave it and move on - never hurts to give it a go.