My mom's denial of her deficits is getting on my nerves. What to do??

I think you are doing a good job. Indeed, your mom likely does not realize the burden she has become to you. She also does not realize she cannot take care of a boat or move to another place. It is all part of her disease and decline in brain function that is part of it. Some narc traits may linger, but I have noticed with my mom that she cannot realize when she has gone overboard anymore and cannot adjust her behavior in a more pleasing manner anymore. This is so hard, but I think you are doing many good things.

We've been making out all right for now, he's safe, has constant supervision from me, aides while I'm at work, and my cousin also helps out. My sister dumped this all on me, she's checked out. Won't even visit.
We're managing. Dad is deluded about everything, but is calm for the most part. The aides and myself keep him as well entertained as we can. He saves his worst behavior for me; the aides tend to be better than I am at redirecting him as necessary when agitation or sundowning kicks in, and his neurologist started him on a low dose of seroquel in the later afternoon, which has been helping a bit.

I sometimes feel guilty when I do vent here- as heartbreaking and awful and frustrating as dealing with this can be, there are lots of folks out here in even more dire circumstances. I at least have aides and a cousin as support (and the biggest piece of this puzzle is that Dad has LTC), but there are many being crushed by the weight of trying to do this with less/ no help, physically or financially. My heart goes out to all, and I count my blessings and try hard to practice gratitude every day.

But I'm under no illusions that he will not have to go to a facility at some point. I want to honor Dad's wish to age in place as much as I can for as long as it's possible. He's raised his hands a very few times, directed only at me, but I think, in retrospect, it was my own poor handling of the situations that caused the escalation- I've since started practicing better techniques and have not had things get out of hand like that for a while. But it weighs heavily on me. I know we'll get to the point of having to place him. He still ambulates very well, is in very good condition physically, is able to toilet himself, is not yet incontinent and has no serious eating troubles- YET. But he sometimes takes bites that are too big, or he doesn't fully chew- I've had to do the heimlich on him twice in the last 7 years. I don't think it's a swallowing issue, we try to keep an eye on how much he's cutting things up, and tell him to take his time, chew more and not rush, but I fear this, and swallowing, becoming a problem as he declines.
I have a feeling that when/if wandering becomes a serious issue at night, that will be what pushes the situation. He doesn't wander very much now, we try to keep him entertained so he doesn't "fixate" on things he thinks he needs to do elsewhere in the house, and he sleeps through the night except for bathroom breaks, which he also has supervision for. I have been sleeping on an air mattress in the room next to his at night since an overnight fall a year ago; I have a motion sensor next to his bed that sounds a remote alarm box I keep with me, and can get to him as soon as he stands up. I did major detective work, removed anything I thought he could possibly stumble on, and he hasn't fallen since, so that's great, but he will again at some point.
But we're under as much control as possible. For now.

So that's my really, really long answer to your short query! I hope you're not sorry you asked!

Fun with anosognosia, a lot of us know all about that only too well...
I can hear your frustration, but know that you'll get nowhere with her.
My dad is about 8 years into Alzheimer's, and it was bad enough early on to see him slipping, and hear him saying to himself or to the cats "I'm so confused, I don't know what the hell I'm doing...' That absolutely broke my heart, that he was failing and knew it. He was an electrical engineer and master mechanic, and now he cannot complete the simplest tasks.

But then fast forward just a little bit, and then it was "What the hell are you doing? What did you do to my (insert thing he himself just ruined/broke here)?" I had caught him smashing another $85 Braun self-cleaning shaver in the bathroom sink, and tried to stop him, but there's the broken thing in his hand, and there he is, cussing me out and telling me "YOU just did it!!!" (You will think that surely, you're going to completely lose it and crack up the first time this kind of thing happens. You can even try to tell your friends all about what you're dealing with- if they have no first hand experience with hard-core dementia, they might not even believe you at first!)

Dad is completely disconnected from reality. His short-term recollection, even for things he has physically just done himself not more than 10 seconds ago, is completely obliterated. Yet, the worse he gets, the more he believes he's on top of his game. He lives with myself and a cousin, but he will tell his aide every day that he lives alone, he says goes to the grocery every day, always asks her if she'd be needing a ride home (he doesn't have a car or drive anymore), he doesn't even know he has children, let alone that one lives with him, and thinks he takes care of his finances, and everything else, when it's the other way around.
Or better, from a man who never swore on a regular basis, and was the best-natured, most easygoing guy- "Get the F*@k away from me. I know what I'm doing. There's nothing wrong with me, you stupid Bi#ch. Get out of my house! You're the one with problems." And he's saying this as he's trying to call my aunt with the TV remote, and I'm trying to give him a hand. He doesn't know what Alzheimer's is anymore, much less that he has it. He bought a LTC policy years and years ago because the thought of becoming a burden on his girls or being in a nursing home was too much for him, and now cannot grasp the fact that the more difficult he acts at home because of his delusions of being normal, the closer he is pushing himself toward the very thing he wanted to avoid, and is acting like the burden he didn't want to become. And this simple logic just can't be used with them, it's meaningless. To them, THEY'RE normal, and YOU'RE cheating them, lying to them, stealing from them, breaking and hiding their things, not FEEDING them! Yes, Dad has no real feelings of hunger or satiety anymore, so couple that with the complete loss of short-term and you've got a guy telling his daughter that just gave him a big dinner that he ate every bite of that she's mean and won't feed him. Or that you're "gaslighting" them, trying to make them think they're crazy!

The neurologist told me about anosognosia years ago, as something so common to pretty much expect, and that it was one of the most frustrating things to deal with. "Steel yourself- the worse he gets, the better he'll think he is!! He'll accuse you of everything under the sun, you must not let it get to you. You know, and your family knows the truth. Whatever the truth is, he's either not going to believe it or will just forget anyway. He is very lucky to have such a daughter to take care of him, whether he realizes it or not."
So that's what you have to hang on to- you're doing your best, it will not be appreciated, and you'll feel sick of it A lot. I am still trying different tactics to deal with the frustration myself.
It is so VERY frustrating, so vent away!

It really is frustrating and exhausting to have to deal with certain aspects of dementia. I think that many people think that it's when a person forgets certain information, can't keep up with keys, purse, etc., but, they do not realize that it's much more than that. It's when the LO insist on information that is not true, repeats the same thing over and over, resists care, uses poor judgment and has magical thinking. My LO who needed help with ALL of her ADLs, was certain that she could live alone, as long as her neighbors looked in her a couple of times a day!!! In my case, the comments and magical thinking eventually stopped, as she progressed.

www.webmd.com/schizophrenia/what-is-anosognosia#1

Piper, I don't know if knowing that this condition has a name and that it is fairly common in Dementia patients helps at all.

What may help is learning specific techniques to deal with it. You can contact the Alzheimer's Association, NAMI, and watch Teepa Snow videos.

You can see a counselor. You can come here and vent and scream.

Hopefully, others will be along with some more concrete suggestions....