Tactics for hostility and accusations?

Sounds like you're describing my mother, she accuses us of many things, stealing her wine (she has an alcohol obsession, this is new by the way, we have tried non alcoholic, watering it down, giving her one standard drink a day-nothing works-she somehow manages to go to the store and buy more) anyway I'm rambling; my mother was on the warpath on the weekend, she gets so agitated she shakes, shouts and usually runs away from me for a few hours which is frightening. Shortly after she has no memory of it and I'm left emotionally drained, devastated and depleted of any energy to keep caring for her. My heart goes out to you, please know you are not alone with these feelings of utter frustration. I always have to remind myself that my true mum, the one that was so kind and gentle is in there. Maybe a neutral caregiver is the answer for you, hang in there, try to be the reasonable one she can't because of this evil dementia. xx

Thanks @pamstegman. These days she's not drinking at least, but she does have xanax and pain killers, and I suspect she abuses the xanax. I have contacted a social worker we've dealt with in the past and asked for something, anything, to get the ball rolling for a state-appointed caseworker for her, so they can take over guardianship. I can't get anywhere with her. I take one step forward and fall two back because she runs hot and cold. Today, I call her to remind her she has a doctor's appointment. She refuses to go, says they're doing nothing for her (this is for an old bedsore), and she wants her phone cut off and other stuff. Maybe I should just call the cops...

Better that you call the cops first, report her disorientation and make sure they have your contact information. If they want to take her in for a psych eval, let them do it.
Look up alcohol related psychosis. Some patients benefit from thiamine (B1) injections from an MD. Alcohol depletes many things, but a loss of thiamine badly affects the brain.

My mom is on a roll. Shopped for her Saturday, before the big storm hit, and we drop off a couple bags of fresh fruits and vegetables and she was on the warpath, shouting at us.
We left. No use engaging her.
But she thinks we stole from her. This time, cash. I told her I took some out for shopping and I've given her receipts, etc. Or if she tried to give me cash after I shopped for her, I turn it down, and told her we had a standing stash to use. Was no problem until the other day.
She even had the audacity (or her dementia did) to call and demand I return her spare apartment key and bring her her debit card (which I had because she never leaves her place except to shop once every month or two or to visit the doctor). But she said she was giving me one hour or she'd call the cops! I'm horrified because I do know it's the dementia, but it still hurts to be talked to like I'm a criminal, especially when I've watched out for her since I was a kid, and back then it was drinking (making sure she didn't fall asleep with a lit cigarette, or making her breakfast in the middle of the night), or as a teen, picking her up from bars when she was too drunk or even bailing her out of jail after she got busted for a DUI. (Who wants to bail their mom out at any age, especially as a teen?) Or, I've lent her money or given her money, or I've played secretary and sorted out bills or paperwork, etc. After four decades of this (just about, anyways), I feel worn out and like a fool.
So, haven't talked to her since Saturday. Usually the drama calms down but I am seriously thinking of just letting it all go to a state-mandated caregiver. I've had enough. I have to drive her around, sit in for hours on doctor appointments, wait for hours while she shops, help out with this or that problem, and all I do is end up getting yelled at or treated like dirt. She has issues with the entire family and I'm the last one she has contact with and now this ... again and again.
Maybe a neutral caregiver would be the best option. They might better know how to treat these crazy spells. She fights and argues with me every step of the way and I'm plain tired of it.

Mom's doctor knows about the delusions and accusations, so we have that.
My mom will say she has "proof" of theft. What is it? A photo she took 10, 20, 30 years ago of some item she misplaced or gave away. Just because she had a picture of a plate that hung on a wall means nothing in terms of proof, but to her it makes sense.
Lots of people, just from talking to her, can figure it out pretty fast that she has issues. She'll say weird, off-the-wall stuff, borderline racist things, or ramble so any accusation she might make I can't see going anywhere. Especially since she developed an obsession with a neighbor many years ago and she called false police reports in on her (saying she was a prostitute and a drug dealer), which the police got wise on and I got contacted by her doctor that she was being investigated, albeit informally. I finally told her to cut the calls to the cops, because she admitted to me she had to lie about the neighbor to protect herself, I told her that if she got caught in these lies she'd be in a world of trouble, so it did die down. But obsessions spring up anew, apparently!
I have no brothers or sisters to help, and no other family around. My mom broke off contact with the entire family more than 20 years ago, and I let myself get pulled into the drama, in a way, by siding with her. (Now, I think mental illness was at play.)
But we are looking at applying to get her into assisted living (since there's a 2-year waiting list around here for many and just applying at ones where they also have options for nursing home care or an alzheimer's ward) and guardianship and other things. It just ends up either my husband is the enemy or I am the enemy for not taking her side. I get it that she's kind of turning back into an unreasonable child, but she's had this obsession with my husband for years. She had a stroke 12 years ago and it was right around the time I had my first date, so she keeps dragging it up that I "changed" somehow and deceived her. Um, no, I just want to enjoy my life with my husband and not live only for my mom!

She is no longer in touch with reality. Get her committed to a home before she lands your hubby in jail with her delusions.

Many people with dementia develop obsessions. That you realize her suspicion of your husband is part of her dementia is good. You're doing everything you can be doing (changing the subject, leaving, etc.).

Does your mom take anything for anxiety? If not, that might be something to discuss with her Dr.

Heidi73, it's possible that the accusations are a somewhat confused way to deal with her anxiety about your husband keeping you from devoting your "full attention" to your mother. Lots of threads here about parents trying to come between spouses to keep their primary place in child's heart (sometimes on purpose/sometimes not). You can redirect like you have been doing; you will need to set boundaries with her to let her know it's not acceptable to talk about your husband that way. Dementia removes the filters from minds - sometimes the person is more honest about what they feel even if they don't tell you in a logical way. If it's really bizarre, document what she says to keep from having any abuse allegations made later (you don't say if you have siblings, etc that might get involved). Get your notes to her doctor so that they can be evaluated at next appointment. Otherwise - deep breathing helps me with my MIL (Parkinson's patient who won't admit to cognition changes), physically getting up and leaving or opening my book and stating that I can hardly wait to find out what happens to my fave character. Sorry you are dealing with this - my MIL is still waiting for my husband to come devote his life to taking care of her and moving her in with us. Not happening.