Mom needs schedule reversed so caregiving isn't totally disrupted. Drinks wine or sleeps all day and prowls at night disturbing anyone in the house. Keep removing alcohol but she can drive to get more (no food, just wine). How to start over to reverse this curse?
If her doctor is enabling, someone needs MPOA or at least a HIPPAA waiver. Get Mom's records. If there is NO mention of her alcohol abuse or dementia, or no mention of any psych testing, tell the doctor that they will either address this or be reported to the state medical board. Don't be shy, and file that complaint. You may find you have lots of company complaining, or that the PCP doesn't see Mom enough to know anything about her situation.
I am less concerned about Mom and more concerned about her potential victims. Start with sister, and support her to stop enabling. Then try to save Mom's potential driving victims.
Mom can and will do herself in and you can't save her from herself. You can decide to let her be miserable by herself. Set boundaries and stick with them. Help your sister break free from Mom.
Eventually one of you will get the call that Mom is in hospital. Insist that she is an unsafe discharge, that there is no one who can take care of her, and get her into a LTC facility. That is your best, safest path forward through the mess your Mom has made.
Living with alcoholic is a losing battle. More likely facility /rehab for alcoholics required. It is a problem you cannot correct alone, it needs team approach.
You may need to place Mom. Hopefully one of you has POA it will be easier. If no money you can apply for Medicaid to help offset her care. Her SS and any pension she has will go towards her care.
If Mom winds up in the hospital and rehab especially, tell the Social Worker that you will not be bringing her home. She needs 24/7 care you can no longer give. Do not let them tell you that there is help. There is not enough help. Once you walk out the door with Mom, she is your responsibility. Rehab is a better place to have her evaluated. They are usually attached to a Long-term care facility so transitioning from Rehab to LTC is easy. The SW can help you start the Medicaid process if Mom has no assets.
Hide the car keys so she at least can't access the vehicle. Hide her money so she can't buy it (put it in the locking cabinet in your room), put an alarm on her bedroom door or use a baby monitor so she won't wander out of the house at night (which she is likely to do even without a car or money).
Find activities for her body and mind during the day so that she burn energy and can hopefully sleep at night. Reversed body clock is a very common feature in a phase of dementia. We had my elderly LO fold stacks of kitchen towels and sort things several times a day. We purchased a used portable table-top exercise pedaler which she did for 20 minutes while watching TV. We had her read aloud to us, chop vegetables, walk to the mailbox (she was 100+ yrs old). Doing this helped her to not need Tylenol PM or other sleeping aids, at least for about a year.
Talk to her doctor about meds. Dementia is a moving target with behavior phases. Be prepared to continue to problem-solve as new behaviors appear.
1. With a diagnosis of dementia/Alzheimer's she should not drive for a variety of reasons.
2. While under the influence of alcohol she should not be driving.
Disable the car so she can not drive.
Unfortunately you are dealing with 2 diseases.
Dementia and Alcoholism.
Depending on the degree of alcoholism she may need medical help to stop.
Is her doctor aware of the drinking? If not they should be made aware as it can effect other medications.
Is there an Adult Day Program in your area that she could participate in? That would keep her busy during the day an possibly "reset" her clock.
The alcohol problem needs to be addressed first and for that discuss options with her doctor.