Dear Beverly,
Re: behavioral management of the vocal tics, this is certainly easier said than done. It's not as if your son is planning his behavior and displaying control over it. The nature of such tics is that they are involuntary in nature.
Having said that, sometimes incentive plans can bring about some change. What you might try is rewarding your son from period to period during the time he is at home (e.g., one hour at a time). He would receive his reward whenever he goes through a period without displaying a certain tic (focus on only one tic behavior at a time). Do not punish him for displaying the tic. Remember, if the behavior is truly a tic, it is not deliberate and voluntary.
Re: medication, pharacologic treatment of TS is not a simple and straightforward proposition. Several different classes of medications are often employed, usually in some combination. Antihypertensives and selective serotonin reuptake inhibitors are frequently prescribed. But it's usually sensible to allow sufficient time to see the results of any particular medication, and try not to expect immediate, dramatic results. Also, the nature of tics (both motor and vocal) is that they wax and wane, even without medication. Aggressive treatment of TS with medication makes perfect sense, as long as it's accompanied by patience and deliberation.