I have all the responsibility of caring for my husband with zero authority. He has/had and extremely strong personality. I can't get him to go to bed he spends the night watching porn, reading comics and eating. When he does finally go to bed it means "we" start his day at 7-8-9 PM after I have done my entire day, (bill paying, marketing, food preparation, laundry, housework, etc.) He is difficult to get up his schedule is impossible. He seems clear enough to do exactly what he wants and then claims he can't do anything else due to his mental capacity. I feel like a maid and clean up person. No family, no friends left they are sick of "us". I don't blame them.
I think you sound burned out! How long has he had dementia? He's on the fairly young side so that's really too bad that he already has dementia.
Can you describe what kind of dementia behaviors your husband has? Is he safe alone or does he have to be supervised so that's why you are burning the candle at both ends?
Can you adjust your schedule to be a little more like his? How early are you getting up? If you even worked on getting yourself to bed a little later and getting up a little later, without having to turn completely nocturnal, this might get you a few extra hours of sleep.
Can you bring in some help? I would bet that your husband would be against this so, bring in help for YOU. Not for him. Someone to do some chores to free you up to do stuff with/for hubby. They could cook, clean, do errands, etc.
If you could get someone to sit with him at night so you can go to sleep, that would be nice too.
Though he is a strong personality, you can try to set some boundaries. I do not suggest trying to MAKE him get up/go to sleep when you think he should as it would probably be a losing battle. But there may be other things that are putting a lot of stress on you that maybe you can change.
Best of luck.
Like Alva said, oftentimes Alz/dementia becomes too much to handle alone at home and the sufferer must be placed in Memory Care. Please research some Memory Care ALFs in your area and line your ducks up so you'll be ready if and when the time comes to place your husband. You can visit him there as much as you'd like and still have your own life apart from your husband. Based on what you've said in your profile, it sounds like he needs placement NOW!
Wishing you the best of luck.