What do I do about mother who is getting mean aggressive and telling lies that she believes is true?

What your mom is doing is so common that it has a name.
Confabulation. Here is a link that might help explain it.
https://www.healthline.com/health/confabulation

One thing that you must remember with all things dementia is that whatever behavior is being exibited today will be different in the future.

My aunt had an obscene phone call she spoke of that actually happened to her neighbor. She accused an old man who brought her a gift of making an obscene gesture indicating that he wanted to have sex with her. She called the police and they talked to him!
Those type events passed and she went on to believing everyone she was asked about had moved into an apartment. “Have you seen your friend lately”
”Oh she moved to neighboring city into an apartment”. At first I believed her but when she was on to about the third person ( a 15 yr old great niece) who had moved into an apartment I realized that something was wrong with these stories. I began to piece together that her sister, my late MIL, was prone to giving bizarre answers to some questions and my SIL would say her mother was lying. Both of these women stopped this as the dementia progressed. If asked a question today aunt will simply say “I don’t know”.
Your mom’s stories are hurtful and because they are delivered with what appears to be sincerity it does make for an embarrassing or awkward moment with strangers.
Depending on the person she’s talking to when she announces that you came in drunk again, you can offer a smile or shrug of the shoulder or a follow up phone call. Some people have cards printed up that explain that mom is suffering from dementia.
I think it’s harder when it’s our own mother as opposed to an aunt as we are more sensitive to a parents comments.

You are in a different land and the more you learn about these things the better in order not to take it personal.

Now aunt has started saying things about people in general. They only do what they do to get money. I just say, yes. People generally want to get paid for their work. We will talk about how that isn’t the same thing as stealing (which it seems she’s implying). She will agree and then in the next breath say, “it’s all about the almighty dollar” Lol

Big hugs to you and maybe it’s time for a break to gain perspective. Don’t discount how much a weekend or even an afternoon off can do to help refresh our spirits. No matter how much we love them or how easy they are to care for, it wears us down.
Feel better.

This post reminded me of an instance with Mom.

I had been talking and I found out she was married to a guy I dated 50 yrs ago. The RN told Mom "your daughter used to date my husband" Moms response was "yeah, she got around". Which was far from the truth. I was so embarrassed.

You know that NO ONE in this world has the words to convince someone with dementia. The part of your mother’s brain that knows fact from imagination is shattered, like a glass dropped on the floor, and just as that glass cannot ever be made to hold water, a dementia sufferer can never again be made to understand and reason and realize truth from otherwise.

If you need help in finding a way through this problem ask a trusted friend or acquaintances to help you. You may find ways to providing for her by adding home helpers to your day or night, or you may find that it will be MUCH BETTER for your mother to be in a residence where she will receive professional care at all times of the day or night.

Dementia never gets better, and you must prepare yourself for the future, when she will become harder to care for than she is now. She is NOT lying about you, but rather she is attempting to convince others of what her damaged brain is thinking of as HER TRUTH.

You do not have to feel hurt or angry about what she says, but you do have to take good care of yourself, and that means that you must convince yourself that her comments are coming from a mind that cannot change and cannot think differently than she is now.

If in your heart you believe that it’s time to find your mom a full care placement, then your decision is fine.

Hopes that you find peace as you move forward with her care.

Dementia normally reaches the point where you can no longer care for your mother inside of the home. The behaviors are just TOO outrageous, dangerous and aggravating in general. Now is the time to start looking into Memory Care homes in your area before things get even worse. Then you can visit all the time.......and go back to being the daughter instead of the caregiver. And you'll get to leave when her behavior ramps up and gets ugly. It's a win-win.

Good luck!!

One of the reasons I decided to place my mother into long term care is that caring for her had almost completely destroyed any loving feelings I had for her - call it compassion fatigue or burnout or whatever, the bottom line is that wasn't fair to either of us.