Can doctors prescribe vicodin to help ease withdrawal symptoms?

No. I'm assuming some type of opiate withdrawal? But no they can't against the law. Not likely to be effective anyway. Suboxone and subutex are only approved meds at this time to be used in doctors office and doctor needs training and special license to do this.
If they break law. If you are opiate dependent, physicians who prescribe vicodin for anything other than a bona fide pain condition (and particularly if they prescribe it for withdrawal) are breaking the law. And you are too. Only 2 drugs are legal - Methadone (in programs only) and Buprenorphine (suboxone/subutex) which can be prescribed by specially qualified physicians.Clonidine/other drugs can be legally given.