I'm a recovering crack addict, but I had to hit a really low bottom to get to that point. My bf, at that time, had been smoking crack for decades. I let him go when I chose recovery. He died a couple years ago.
I had abused other things, but crack is the one thing that brought me to my knees. I know you care about this friend, but I'd recommend keeping your distance. Most crack addicts think nothing of stealing whatever they need to support their habit..family, friends..doesn't matter. I led a pretty high-risk lifestyle, and am grateful my true friends stayed away from me, TBH.
You will never understand the pull of addiction unless you are an addict. It's not a moral failing, it's just the way it is. Heck, I DO understand it, but still get angry when someone I love is in the depths of active addiction.
Hugs and prayers,
Amy