Mom's gambling again and has taken cash advances from credit cards. Five $1,000.00 withdrawals in one night and she didn’t remember. Any advice?

Can any family member take away or cancel her credit cards and/or notify the credit card company to maybe limit the amounts she's allowed to get? Perhaps get her one of those store bought pre-paid debit cards and just add limited funds to it? Some banks now offer pre-paid debit cards for a minimal monthly fee that separate from a bank account debit card, and the customer can manually add funds to the account themselves or have a certain amount automatically added monthly. The fees are very small. As little as less than 2 bucks a month and less than a dollar to add funds manually. I use mine for shopping online or parking fees because I don't trust using my bank debit-card or credit cards online or public parking.

You have excellent advice below. If this is a case of dementia, as suggested, it may be too late for POA if there has not been one appointed by your Mom. It may be time for guardianship which would mean that you, another qualified family member, or a licensed fiduciary appointed by the courts act in behalf of this woman financially. It does sound as though she is now a danger to herself, and should not be alone and on her own taking pubic transit anywhere, let alone the casinos.
Think carefully now about whether or not there is a diagnosis, whether or not a family member is QUALIFIED and WILLING to take on the difficult task of being guardian, and of how to proceed to protect your Mom.
So sorry you are facing this down.

While of course the gambling and money issues is a serious issue, look ahead a bit.

Are you willing to be the one to move in with her (or her in with you?) if/when it's determined that she can no longer live alone?

If not, better start making plans now so that it doesn't happen.

If your mother has been diagnosed with dementia, it's time for you to go to the probate court and file a petition for POA and conservatorship over her.
How does she get to the casino? Does she drive? If so, please consider the other lives she puts at risk. Driving with dementia is the same as drunk driving. Go to the police in advance, show them documentation that she's been diagnosed with dementia explain to them that you are going to "steal" the car. Then park it somewhere where she has no access to it.
I'm going to assume your mother lives alone. She should not. Call APS if you have to and let them place her. You are not responsible for her gambling debts or what she owes her credit cards. Do not take any responsibility for that.
If you get POA and conservatorship over her, that is when you can change all her accounts and shut off her credit cards. You will also be able to place her too.

Put a freeze on her credit, so she can't get anymore cards, and cut up the ones she has. (Ideally, you want to cancel them.)

Don't lose the password to unlock her credit again, because it's the ONLY way to do it. Contact each credit reporting agency to freeze it. I did this with my folks' credit when my dad got sick just as a safety measure. I took over their finances, and as Mom had dementia, she had no need for credit after Dad died. I never had to unlock her credit for the rest of her life, and that was four years.

No one will extend credit to her or give her loans if they can't check her credit reports, and that's what freezing it does.

If you don't have POA for Mom, frankly, I'd pretend to be her when calling to do it. You aren't taking advantage of her financially; you're protecting her. THEN do what you must in order to get guardianship of her and her finances.

https://www.nerdwallet.com/article/finance/how-to-freeze-credit

You state in your profile that your mom has dementia.
She should not have access to her bank account or credit cards.
The December 2021 incident, is this the same as the 5 withdrawals of $1000? Or has it happened again where she withdrew money?
She needs to be supervised 24/7.
As to staying awake for 2 days that is entirely possible if you are a gambler. I have known some and 2 days is nothing to a gambling addict.
As to the lying. If this is the gambler, that is part of the addiction. But with dementia that puts another "spin" on lying. It might be the dementia and not recalling events.
If she is living alone, she shouldn't be. If she is living with you (or you with her) and you do not think you can keep her safe she should be placed in Memory Care where she will be in a secure area not able to run out in front of a car. (or get to a casino)