Dementia Dad has such vivid delusions, last night's broke his heart. Any advice?

It started yesterday afternoon, he was wandering the house, without pants I might add, "playing" with the puppy. I just went about my day he wasn't hurting anyone just wandering. Then later that night ... it got quiet... just like when my kids were up to something I could tell something was off. I found him on the floor in the middle bedroom, panting, pants-less, rolling back and forth.
"whats up?"
"well I was trying to help my wife... giving her CPR so I got down here to do it and I can't get back up"
"Dad... your wife?" Mother died 8 years ago and he has never remarried or even dated.
"Cindy... my wife" cindy was a therapist he had 5 years ago after his stroke.
I called help to get him up and he continued the story with them...he NEEDED to get to the hospital, no there was nothing wrong with HIM but he needed to check on his wife... please could they take him to the hospital.
paramedics left without taking him
I kept digging... What happened Dad...
Well, a few months ago he got remarried to Cindy (if you're following I don't know if the imaginary cindy and the imaginary coleen know about each other but my dad is a hound dog!!) They had gone to the ASPCA and adopted a puppy something happened and he electrocuted the wife and the puppy in the bath tub (we don't have a bath tub just a walk in shower) He managed to drag out his wife and give her CPR and the 5 firemen had taken her to the hospital to help her.
welllllll..... I had listened and calmly asked if all of that made sense to him? He was very very upset ... understandably. I tried to talk him down from his manic moment... to no avail he wandered the house and fretted and tried to call people to take him to the hospital, he never cried he just panted and then I managed to ask him if he could honestly say it all made sense... The electrocution especially.... since he could clearly see there was NO bath tub... HOW could he have electrocuted them .... he stopped and stared like seeing the shower for the first time... and said, I couldn't. he calmed down a bit and has managed to get into bed and is asleep. But it seriously broke his heart, normally my dad is the most calm tender person in the world. He would never hurt anyone intentionally or an animal. no question just wanting to share that. Thanks for listening.