Extreme Insomnia Due to Inability to Lie Still at Night

Hello All, sorry for the long post but I wanted to give some background information without being too wordy.

My 80 year old father is currently diagnosed with parkinsonism. He initially was diagnosed with parkinsons 12 years ago, then lewy body dementia, and now they just call it parkinsonism. Overall his symptoms were extremely minor for the first 9 years and he wasnt on any medication for the disease. But starting 3 years ago, he has suffered from extreme insomnia that has caused his condition to worsen exponentially.

He suffers from an inability to sit still, relax, and lie down at night in his bedroom. He is just constantly moving all night long. He's constantly sitting on the side of the bed, or crawling on the floor, or standing up and checking the light switches or closet door, or playing with his sheets, or undressing, or etc. Its like a switch flips in his brain once he goes up to his bedroom at night and he has full blown ADHD or dementia and is unaware of what he is doing and truly has no control over it. On average, he sleeps less than 1 hour every night now. We want him in his bedroom at night because he is a fall risk and that is the safest place for him in case he falls.

During the day and early evening, he is pretty much out of it mentally and just sleepy in his lounge chair in the living room. He has a lot of cat naps but nothing long; certainly not long enough to make up for the lack of sleep at night. His mobility has also worsened a lot due to the lack of sleep. We've tried the whole sleep hygiene/trying to keep him awake during the day so he can sleep at night but it's very difficult and the few times we've succeeded in doing so, he still doesnt sleep at night. So we've just resorted to letting him get whatever sleep he can. He can go weeks upon weeks without sleeping at night and then finally his body will give in and he will have 2-3 nights of good sleep in a row; but then the insomnia will start right back up. When he does actually sleep, he is like his old self from 10 years ago the following day so we are just so desperate to get him to sleep. We hate to see him deteriorate like this just due to an inability to lie down at night and sleep.

The only medication he currently takes is gabapentin for restless leg syndrome. That said, he claims that his inability to lie still at night is not because of the RLS so we have to take him at his word. And it's not like he's moving his legs all night long either for relief. We've tried increasing the dosage of gabapentin too and it hasn't had any effect. For insomnia specifically, these are the list of medications we have tried in recent years but none have worked.

CBD/CBN (2025)
Melatonin (2025)
Carbidopa/Levodopa (2025)
Mirtazapine (2025)
Zolpidem (2025)
Quetiapine (2025)
Sertraline (2011-2025; for mood not sleep)
Trazodone (2019-2025; sporadically)
Alprazolam (2024)
Clonazepam (2023)
Donepezil (2023)
Suvorexant (2022)
Ropinirole (2018-2022; then switched to gabapentin)

Does anyone here have any experience similar to ours? Does anyone have any advice? We wish there was just some magic pill that could knock him out every night so that he can have a better quality of life again.

Thank you kindly in advance.