Addiction is a very selfish disease, I can't talk from the viewpoint of cocaine, but instead I am an alcoholic. But when I was drinking I was only concerned about, where my next drink was coming from, my sole focus in life was when I'd be drinking again, where I'd be buying my next drink, planning my life around social events I could drink at and blowing of meeting others in favour of drinking by myself, alone at home.
My point is the mind of an addict is controlled by the addiction, and that means that relationships/friends/family become 2nd in the pecking order, and so hurtful things can be said, personally I've ruined relationships due to alcohol, something I regretted when I got Sober.
The best advice though is to look after YOU, the other thing about addiction is an addict can't be helped unless THEY want help, they can't be forced, and so the main thing for family/friends is to never loose focus of their own life, and in time the addict may change. If not then at least you haven't postponed your own life waiting in the hope!!