Sleep issues; any sleep meds that you can report a positive experience with for loved ones with dementia?

My FIL has vascular dementia and is slowly declining. We put a camera outside his doorway just to observe if he is sleeping ok, he sleeps downstairs, we are upstairs. We noticed he doesn't sleep very well at all, maybe 3-4 hours at most and this is 1-2 days a week. Sometimes he doesn't sleep at all and we notice a negative change in his behavior. During the day when he doesn't sleep the night before he is in a foul mood the whole day - refuses to take meds, refuses to eat, hides in his room, more confused, much more paranoid and accusatory (I guess I would be too if I weren't sleeping haha). We have tried melatonin 5 mg, that was too much. He slept the entire next day without eating, only got up to use the bathroom. We're trying 3 mg but it doesn't seem to have any real effect. We have an upcoming appointment in a couple weeks with his primary. My questions is, is there any sleep meds that you can report a positive experience with for loved ones with dementia? I've heard restoril can help???