Rotigotine reduction symptoms - Dopamine Agonist

My Husband was on 8mg Rotigotine/Neupro patch, the 8mg made him so sleepy he was unrousable at times and he was hallucinating. It was reduced to 6mg and he was more alert on the 6mg with the hallucinations almost gone, the reduction in patch strength is being done week by week now he has been on 4mg for 4 days and he is again very sleepy and slightly less with it. Has anyone any ideas as to whether the symptoms I’m describing are due to the reduction/tapering off of the Rotigotine?