It would be important to discuss this with his psychiatrist to rule out the potential of tardive dyskinesia. This is a long term movement disorder that can be caused by this medication. This can become more evident when a medication dose is lowered or discontinued. A neurologist who is a trained movement disorders specialist would be able best able to diagnose and treat this potential concern. Also if it is noted you could discuss potential options with his psychiatrist.
For more information google "Patient Education Tardive Dyskinesia' (note as the site itself says "some of these medications may be medically necessary). Also this is a clinically accurate webpage on Emedicine on tardive dyskinesia. that you could discuss with whichever doctor follows up on this concern.
Very good reply by ILADVOCATE, and I agree completely. And thankyou,
ILADVOCATE for your reply.