How do I help my mother, who lives alone, stop self medicating with anything she can get her hands on?

I'd suggest that you look for support for yourself by attending some Al-Anon meetings. Your mother knows she has a problem. She's addicted to alcohol (or she wouldn't hide it). She is also drinking with medications that likely say "no alcohol" on the bottle.
Arguing with her likley won't help. By attending Al-Anon, you may learn tools to cope with your own frustration. That in turn could help your mom.
Alcoholism is not rare among elders, and doctors are just starting to pick up on that. However, in the end, there's little to be done unless the person with the problem cooperates or her doctor believes she should be hospitalized.
Take care of yourself. This is a frustration many share.
Carol

Do you think your mother might be lonely. Sometimes people use alcohol as a companion. And if no one is there to help them keep the use in check, they can drink more than they should. Does she have friends? Has she always had a drinking problem? One thing you should caution her is to never take Tylenol when drinking. Tylenol and alcohol can be a toxic combination because of the effect of acetominophen on liver enzymes.

About her OTC drug use -- there is not much you can do if she is living independently except encourage her to cut back. And to never take Tylenol when she is drinking.

I signed off a little too fast on the last message. One thing that is important to know is that you can't control what your mother does if she is living independently. You can only control how you react to what she is doing. Sometimes it is better to distance yourself emotionally and not get dragged into the problems that she won't let you fix. Most true alcoholics cannot stop drinking because someone else wants them to. However, many can cut back if they are socially active. (Sometimes I wish our elders lived with roommates like the Golden Girls. I think it would be much healthier for them.)

Thank you Carol and Jessiebelle.Her drinking problem spans about 15-20 years now. All of what you say is true. She won't be able to control it, if she lives alone and she does. I can't help her if she doesn't want help herself and I don't see that she will ever give up the bottle. But even when my Dad was there, she just hid it better. She drinks around the clock. The main reasons we moved them closer was because her drinking was pretty bad and she was still driving and I knew she was going to hit someone or kill someone or kill herself. I was trying to save them from that. The house was almost inhabitable as she is a semi-hoarder (can't throw any paper away and OCD of bags, bags and bags of bags. Dad did nothing around the house because he was in deep depression and hadn't bathed for months. Yuck. He also has dementia and is verbally abusive to all of us.

Back to the present, she now lives alone and the paper is piling up and begrudgingly, she lets me throw away a few pieces at a time, but it is still a mess. She's now losing bills to pay, and sleeping pretty much all day, (because she forgets if she has taken her pills and takes them again). Now with dad on Medicaid, the state is threatening us with the "Money Follows the People" program where they ask the long term care patient, "do you want to go back to the community" and of course my Dad says yes. There is no room in their paper-laden one-bedroom apartment for a full time caregiver, never mind a wheel chair as he doesn't walk anymore. Meanwhile, Mom is forgetting appointments and the list goes on. I'm pretty much tired of it all and planning to remove myself as POA if this continues. Neither siblings cares about any of this. Please don't ask me if I asked them for help, because i have. For three years now. One only wants their money and refuses to help unless she has access to the checkbook and the other lives further away and also says, "whatever".

Help!