How to handle agitation/are we nearing the end?

My Dad has progressive supra nuclear palsy, diagnosed originally as parkinsons. He has declined fairly rapidly in the past couple years. This year alone he has suffered 3 falls, both resulting in a head injury, although all CT scans are clear. Last year, he choked and lost consciousness for about 36 hours but went to rehab and returned home after about a month. Since that hospitalization we have noticed a pretty marked increase in dementia. Currently, he is unable to do much on his own and is confined to his wheelchair, bed or lift chair. The most recent head injury occurred late last week, superficial injury, no concussion or hematoma. Since then, he has increased hallucinations, increased sleepiness, and today is very agitated. From what I understand, agitation is to be expected with his condition and he is on medication to help with it. We try music, reading to him, giving him a pillow to cuddle, but sometimes, it doesn't seem like much calms him down. Each injury, cold, change in meds seems to really throw him off and now we have a combination of all three, although he is recovered from the cold. His doctors are aware. I guess I'm just asking for advice on how to keep him calm, if we should even try since this is an aspect of the disease. He has 24 hour care at home. I'm also extremely sad because we seem to be losing him. I don't know if we need to contact hospice yet. We knew things were going to be bad but this is just awful. Sometimes he seems so frightened by things that aren't there, other times he carries on a conversation with an imaginary person and just laughs and laughs.