How do I help my dad when I'm constantly tired and frustrated?

I (31M) have posted here before about my dad, but I just feel at a complete loss once again. Every day feels like an exercise in futility and hopelessness when it comes to caring for my dad and trying to live life.

For some context, my father (71M) lives with me and suffers from vascular dementia, which he was diagnosed with in February of this year after a DAT scan confirmed that he had a stroke last year that caused it to kick off. He had been having some memory issues before in the last couple of issues, but we both dismissed it as him just getting older. Anyway, I was prepared in my mind for the dementia diagnosis because my mom also dealt with vascular dementia before she passed away in 2023 (she dealt with it for almost 4 years before colorectal cancer sped up the disease to end stage). But my dad has declined further than I expected in such a short amount of time, and I'm afraid that he's given up despite telling me that he wants to get better and stick around for as long as he can.

Now I'm getting to the bad part of the post (sorry for it being so long already). I'm constantly on edge and prone to snapping at him for the smallest thing. I have a bad temper at times, but it used to take a while before anything would just upset me to the point of real anger. Now it doesn't take all that much when I'm at home with him. Recently, he has regressed back into rearranging furniture and moving his clothes as well as other things in the middle of the night while I'm asleep. Just today, I woke up to him completely naked in the kitchen trying to put on a diaper with his clothes scattered across the apartment, six or seven diapers laying on the floor, the cushion taken out of the living room chair, and his pillows and blanket flung about. I asked why, and he told me that he thought he had wet himself before telling me less than 30 minutes later that he didn't know why he was naked to then also tell me that the last thing he remembered was that he was working with the chains on his truck or the bed of his truck (he has never had chains on his truck, and he didn't go outside last night). I wish I could say that was the worst incident since his diagnosis, but it barely scrapes the top 5.

He still has trouble figuring out where the bathroom is even though I keep the door open and both the light in the hallway and the bathroom stay on all the time. He still pees in the floor even though the lid is up on the toilet (just yesterday, he peed in the floor right next to the toilet and proceeded to just stand in it until I showed up to use the bathroom myself). He has trouble with pooping now because he wipes and then puts the toilet paper on the floor instead of the toilet (right after I finished cleaning up his pee yesterday, he pooped and used a diaper as well as toilet paper to wipe himself and then threw all of it in the floor; he's also had an incident where he threw away his poop in a cereal box and put it in the kitchen trash). He seems to always think that his belt is broken and fiddles with it so much that I have to stop him before he breaks it for real. He gave up on the puzzle book that his nurse brought him so that he would have something to do during the day instead of just watching TV, and he claims that his phone is broken all the time even though it's not and rings to prove to him that it's not (that last part is more just about the fact that he's bad with technology even before the dementia made it impossible for him).

The gist is this: I'm tired of being so angry and frustrated all the time. I know that none of this is his fault and that this disease is doing all of this to him, but it also feels like a part of him deep down blames me or resents me for something and that this is his way of getting back at me because it's always the same actions each day: pee in the floor, rearrange furniture, fling clothes/diapers/blankets/cushions in the floor, and stand around like a deer in headlights. I told him and my therapist that I think a part of him just has a deep hatred or something toward me that manifests in those moments where the dementia takes the wheel and then leaves him to pick up the tab once it's done with its new chaos that it spreads. I try my best to remember that this isn't what either of us pictured when he moved in with me, but it's hard to do this same song and dance every day.

If you've stuck around long enough to read this, then you're likely saying to yourself "Why hasn't he put him in a facility or gotten more help?" The answer is that he has help in the form of the VA checking on him every so often and doctor's appointments to figure out any issues that come up when they happen. As far as other help, the closest family we have is 4 hours away, which is his brother. His sisters all live either in Virginia or Kentucky, and my half-sister also lives in Virginia (my dad and I both live in Arkansas). My oldest aunt has already said that her caregiving years are behind her and that she wants to enjoy her retirement, and my sister is a cop that is constantly working.

Aside from that, my dad does get Social Security, but I don't believe it's enough to afford memory care like I'm sure that he needs. He also doesn't want to be put in a home because he wants to be with me and help me out so that I can go back to school and finish my degree to start my career (I'm currently on leave from a Ph.D. program in English). I also don't want to put him in a home because I'm afraid that he'll just give up completely because he'll see that I've "given up" on him and just refuse to stick around. But I also have to be realistic and understand that I can't keep going like this because I'm already on fumes as it is.

What do I do?