My Husband Is Taking Klonopin 2 Mg And Trazadone (don't

My husband is taking klonopin 2 mg and trazadone (don't know dosage as he is in rehab center). He has started hallucinating and was wondering if it could be a drug interaction. He suffered anoxic brain injury but was progressing rather rapidly until recently and was wondering if adding trazadone could have attributed to his rapid digression. He has taken klonopin for 25 years with no side effects.