What Causes Incoherent And Unmanageable Nature Of A Person?

My father, aged 62, has been under psychiatric treatment for 6 years for Recursive Depressive Disorder. During this period he was cured for nearly 2 years. However, though for the last 4 – 6 months he is free from depression he has been found to become increasingly nagging and later in-coherent. For the last 1-2 month we have found him talking to himself or others, completely incoherent. He suddenly lies down on the floor, starts running(with small steps), hugs anyone who is around him, shouts(either someone’s name, or just blabbers incoherently or the words:“minor aberration”). He was admitted in a psychiatric facility for last 1 month where initially he was given no medicines to eliminate the case of drug reaction. Following this when his actions became more uncontrollable(he started jumping and falling face first on the bed, banging an open door, hugging people more, running) pathological test were done. Urine Culture, Chest X-ray, USG(whole abdomen) showed everything to be clear. However the C-REACTIVVE PROTEIN was found to be 51.1(However, the psychiatrists and neurologist finds one things very puzzling and completely reverse to his diagnosis. My father has periods of high confusion when he presents typical symptoms of dementia and very high delirium(all above abnormal activities included), But he too has periods when he is lucid, completely coherent, aware, sharp memory and defies any signs or symptoms of dementia. According to the psychiatrist in lucid times also there should be at least some baseline cognitive deficit no matter how less, and hence the doctor too is at a loss. When he is normal he says that sometimes he has a squeezing sensation inside his head, which is soon followed by confusion and worsening of the squeezing sensation. Soon it becomes intolerable and he loses control and as we see he loses full cognition. If at that time we talk to him he hears but cant comprehend. So we give him Haloperidol drops when he feels the squeezing sensation or as soon as we detect he is starting to get confused. His present medication includes: •     Donepezil (10mg at morning) •     Risperidone(2mg at night) •     Quitipine (150 afternoon + 150 night) •     Haloperidol oral liquid (10 drops SOS) – generally 50 – 90 drops per day My question: •     Is the Diagnosis correct? •      If so then why is he so incoherent and unmanageable at times(nearly 8-10 hrs a day). Also how can he be so coherent and responsible at other times? •     He is in tremendous discomfort. Today whole day he kept running and walking briskly with small steps. Is this ever going to stop? Will he be able to get relief? Please HELP us…If required we can also take him to you next month.