Father thinks it's morning at 1:30 am. Any advice?

Last night, I awoke at 1:30 am because my father had gotten up and turned on his light. He took his morning 1 minute shower (no soap, no shampoo), bathroomed, and presumably shaved and dressed (guessing there). He used to use a razor where you changed the blades but about 1.5 years ago, he could no longer change the blades (too hard for him, vision too poor) so he switched to fully disposable. He claimed about 6 months ago that they no longer "worked" which of course they did but his face was often cut, and the hairs were all different lengths. Finally, I got him an electric razor, and he can shave. He can't properly comb his hair. He got up again at 2:30 am for 10 minutes. I keep my bedroom door open so the cats can come and go, and I can see when his light is on. Early this year, he got up one morning at 1:30 am, did his morning stuff, and went downstairs. I followed him downstairs and asked him what he was doing. He said "It's time to get up." I pointed out the time, and he was surprised. He went and sat in his recliner until dawn.

First, some background. He's bipolar, and when he was manic, he would get up in the middle of the night and tear the house apart throwing things away. Although he is now depressed instead, my auto response system sends me in to a panic when he gets up in the middle of the night, and I can't sleep. I had to take half a Xanax myself which I hate to do. He didn't get out of his room this morning, so I figured he'd had diarrhea in his pants again. I asked him this morning, and I was wrong. He said, he thought it was morning. I asked him if he couldn't see his clock. I bought him a new one with huge numbers that's lit up. He said he just didn't look at it until he was ready to leave the room. I offered to set the alarm (I doubt he could turn it off) or manually wake him each day but he declined.

He is in bed for 9 to 10 hours a day, and he usually doesn't wake at all during the night. He has trazodone an hour before I wake him from the recliner to go to bed. This was originally prescribed because, when he was manic, he couldn't sleep. When not in bed, he spends all but meals and bathroom time in his recliner. He turns the TV on from when he gets up to about 10 or 11 am, and then again from 6 pm to 10 pm but he's often asleep or not paying attention to it. He is asleep 18 to 20 hours a day. He has no sense of time. He now leaves on about 25% of the lights he turns on, and he used to be obsessed with turning lights off. He won't talk unless a simple, direct question is asked, sometimes multiple times. He's been like this for almost two years now. I had a visitor last year, and she asked me if he was alive when she came through. I check for a moving chest most times that I walk past him. Most noises no longer awake him since he's also hard of hearing.

Is there someway to keep him from thinking it's dawn before 6 am so I don't go insane myself? Thanks.