@lulululu You, poor sweetheart.
Could you contact his doctor about giving him something earlier in the afternoon to help with his sundowning?
You're not alone on that island.
My husband was doing the same thing a couple of years ago. It's very scary and hurtful; his sundowning usually started in the early afternoon and went late into the night. He would get upset and very agitated, and say, "He needs to get out of here, our house where we've lived more than twenty years or say he wanted me to leave.. He would look at photos of us and say, "That's Trisha, but YOU ARE NOT TRISHA"! His doctor prescribed Trazodone, which was some help when I could get him to take the pill.
Cannabis is legal in our state; one Sunday morning, I walked into a dispensary in tears and asked if they could help. They were very supportive and helpful, suggesting gummies that helped with relaxation and calming. In the early afternoon, before the agitation starts, I give him a small bowl of nuts and cut-up gummies. I call it "Trail mix". It doesn't make him "high" it just takes edge off. Our doctor at Mayo Clinic is aware and supportive of what I'm giving him.