when one is trying to kick an opiate addiction, the worst thing to do is to turn to alcohol. what happens is that alcohol will eventually take the place of the opiate in the brain, meaning it will eventually cause the same chemical reaction in the brain. i believe this study was done in houston, tx. when a dead bum would be found and still be warm, the doctor would do an autopsy as fast as possible. what they were finding was that the brain was showing signs of opium use, but these street bums were too poor to afford opium/heroin. however, they were able to obtain alcohol. it is believed that this occurs in alcoholics as well. the brain will eventually have the same response.
pretty interesting actually, at least i thought it was.
that being said, your friend has 2 choices - cold turkey or wean off. if he goes cold turkey, the drug will be out of the body in 2-5 days, approximately. intake of a lot of water and exercise might help to flush it out sooner. after that, the only effects are mental.
the thing your friend must do is "retrain" his brain. he must find good pleasure sources, such as exercise, sex, good meals, etc, basically anything that makes him happy w/out getting high. when the brain has seen long term opiate use, it eventually only knows to release dopamine when the drug is taken. retraining the brain is the hardest part, and it's part of recovery.
i am not an expert on this, some of what i have said may be slightly off, but it's pretty damn close. when my ass got stupid a few years ago and got a DUI, i ended up taking DUI classes in california as part of my probation. the counselor was a former alcohlic and heroin addict with 15 years sober. we were taught a lot about effects of alcohol and other drugs upon the brain, and he openly and willingly shared his personal experiences and how he beat his addiction, which was doing it cold turkey and battling it out for a week or two.
opiates are hard to kick because they are so powerful. good luck to your friend.