I'm a type 1 diabetic and I also have blood sugar that drops rapidly. I use a continuous glucose monitor and if I lived alone I would use a calling service. As it is, I have family check on me regularly. I have hallucinated and become delusional due to hypoglycemia four times in the last six years.
There are four things I think might help your mother.
1. Check blood sugar more frequently with her current meter, and tell her doctor when she's been low, to get doses adjusted or advice on when to eat more. The injectable non-insulin diabetes drugs may also make it harder to treat hypoglycemia- it might be better to switch to insulin. It's also possible that the doctor doesn't realize how low she's been and that if he did, he would decide that she should aim for somewhat higher blood sugars and would take her off of one or more of her medications.
2. Get a continuous glucose monitor. Insurance companies are reluctant to cover these for type 2 diabetics (which is what your mother is) but if you can show that the person is having severe hypoglycemia requiring asssistance from another person, they will usually cover it, because they'd rather pay for a continuous glucose monitor than a hospitalization. In the US, there are two companies making CGMs. For those not using an insulin pump, the options are Minimed Guardian, and Dexcom G4. I have used both. They both alarm with low blood sugar and you set the threshhold. Dexcom, unfortunately, vibrates first and then alarms five minutes later, while Minimed will beep from the beginning. If you have to pay out of pocket, I still think it's worth it (I bought a Minimed Guardian and a Dexcom 7+ out of pocket myself). You can reuse sensors on both systems- just tell the machine that you have started a new sensor without changing it. Outside the US, there are other systems that may be available.
Unfortunately, especially for people who have very rapid lows, the systems will miss some lows.
3. You can get a calling service. They call every day at a certain time of day, and if you don't pick up, they call back in half an hour, and if you still don't pick up, they will either call another person or an ambulance.
4. You can get and/or train a diabetes alert animal. Generally these are dogs, and they go everywhere with the person and alert the person if the person is too high or too low (some just alert for lows). They will prompt you to check your blood sugar when they smell that your blood sugar is off. Depending on the person or dog, they may be more or less accurate,- some are extremely good, better than monitors, and others are not. They can also be trained to call 911 if you get a phone that just requires the push of one button and you register with the emergency services so that they know that a phone call from your house and a bark on the other end means that they should send an ambulance.
It may or may not be possible to totally eliminate your mother's extreme low blood sugar episodes without making her blood sugars too dangerously high, but it should be possible to reduce them to no more than one or two per year.