Dear Betti, In our real live support group we have a saying "having PD does not make one immune to Alzhiemer's Disease (or any other disease for that matter). Some of your father's behavior sounds foreign to PD. I would suggest consultation with a good open-minded neurologist. I have a friend with PD who has taken l-dopa for 25 years now and has been trouble with hallucinations that make him very parinoid. Some times the window between too little and too much l-dopa is very small.