Get your friend to rehab. But like some said, he has to be ready to stop, that is the only way it will work. And by the way, regardless of what people say, cocaine is not physically addictive.
Coke is only mentally addictive, there are only very few drugs(types of drugs that is...) that are physically addictive. For a drug to be physically addictive it must actually change the make up of the body itself. When drugs actually alter the chemistry of the body they become physically addictive. Sure there are some physical withdraw symptoms but they are associated with the mental aspect, not exactly the physical. I shouldnt have said it's not physically addictive I guess because its only slightly addictive physically. The only drugs that are supposed to be physically addictive are pain killers, heroin, etc. (opiates)