Elderly woman suddenly unable to walk - help!

We’re looking at a 91-year-old woman dealing with diabetes—she's been on insulin for about two years now—and angina pectoris following a heart attack.

Up until recently, she was doing pretty well, mostly, despite some ups and downs, and she could move around quite easily. But about ten days ago, things started sliding. Her walking got difficult, and it just keeps getting worse. It started with her being slow, but now she can't really move without holding onto something. Sometimes she can't even get up from a chair. Her hands have given out on her a few times too, though they seem to work again eventually.

Her blood sugar and blood pressure seem fine. She doesn't actually feel "sick"—she's got enough energy to chat, think, and read, and her appetite is good. She doesn't get winded when she tries to move, which makes me think it isn't a heart issue, but she just has zero strength left in her limbs.

What do you guys think is going on? Her doctor suggested physical therapy. I don't know, shouldn't she probably get some internal medicine tests done first? If you think that's the move, what kind of tests are we talking about, and where in Cleveland would be the best place to go?

Could this be a neurological thing? And honestly, do you think this is just a motor skills issue, or are these symptoms a sign that her life is actually in danger?

Honestly, whatever the case may be, just let a 91-year-old be; they don't need all that stress from endless doctor visits and aggressive medical interventions.

My grandmother actually made it to 91, and by the spring of 2003, she was using a walker just to get around. As time went on, she just kept getting weaker... eventually, she couldn't even walk with the walker anymore, or even pull herself up out of bed. That total immobility, it just seemed to hit her all at once, even though we’d noticed her fading day by day. I guess... maybe you should definitely have your grandmother's blood work done? In my grandma's case, the tests showed severe anemia, and she was admitted to a local hospital pretty quickly for a transfusion. A few weeks later, they found a lung tumor—lung cancer. They didn't do any intense therapy because of her age, though I don't know the exact medications they gave her during those two weeks in the hospital. She passed away at home within three months of losing her mobility.

Older folks have such a hard time being in the hospital—at least, that's how it was for my grandmother—so I think the most important thing is just providing the right care. Maybe ask her primary care doctor about requesting a home health nurse and a physical therapist to help with hygiene and daily needs. Usually, before that gets approved, they need to run some assessments with a neurologist or a physiatrist and things like that. Some of it is covered by Medicare, but if you want a nurse there every single workday, you'll probably have to pay for that out of pocket. I would personally really suggest having a physical therapist come to the house. If it's possible, it's honestly better for an elderly person to stay at home in a familiar environment where they're comfortable. Moving to a nursing home can sometimes make their health decline even faster, you know? Most seniors struggle with the idea of assisted living, and my grandmother used to say all the time that people only go to those homes when the family wants to be rid of them. I mean, I know a facility is a solution for people who work all day and just don't have the time to care for a seriously ill family member.

Just like Scott Allen10 said, stop bothering her.
With a body that old, anything can happen—from a sharp verbal jab to just suddenly "shutting down." It’s almost certainly neurological. Brain changes, specifically aging and cell death, start kicking in around fifty and just steadily progress from there. There isn't much you can do about it; that's just how the human machine works.

Grandma has had a long, full life. Give her whatever time she has left—however much that may be—to live out her days with dignity, being cared for and surrounded by the peace and warmth of her family. That is what you can actually do, and it's what I truly recommend.

Thanks a lot for all the replies and the support.

We saw a neurologist. At first, he thought we were looking at a stroke, but after doing a carotid Doppler and a brain CT, he figured out it’s actually a blockage in the carotid artery. It’s cutting off oxygen to the left side of her brain, which is why her right leg and arm are basically useless right now. (I didn't mention earlier that it was the right side of her body because it wasn't obvious—it just looked like general weakness, but it turns out the right side is much weaker.)

As for the CT scan, it doesn't show an active stroke, though there's a chance she had one a long time ago without even knowing it.

I'd love to hear what you guys think about the treatment. The neurologist said her age isn't a reason to skip the carotid surgery, but he isn't sure how much of a risk it would be given her history with a heart attack. What do you think? Should we go through with the surgery?
I get where Scott Allen10 is coming from, but I have this feeling that surgery might be the only real way forward. I wish it weren't true, and that we could just expect a major improvement from medication alone.
Supposedly, they can even do the procedure under local anesthesia. Here are some threads discussing it:

Regarding the meds, being a layman, I expected a whole pharmacy's worth of pills, but she only got Bayer Aspirin and Lipitor once a day. Do you recommend anything else?

Here are the results:

CAROTID COLOR DOPPLER:

The right CCA is occluded throughout, as is the right ICA; the ECA shows retrograde flow up to the bifurcation. No signal in the right ophthalmic artery. The left ICA has high-grade stenosis at the origin due to a semicircular plaque (80-90% stenosis, PSV: 403 cm/s).

Both vertebral arteries show significant compensatory hemodynamic acceleration.

BRAIN CT: old ischemic lesions in the right frontotemporal and right cerebellar regions.

Dx: Right-sided central hemiparesis.
Right common carotid artery occlusion.
Left internal carotid artery stenosis (approx. 90%).
History of cerebral infarction (old).
History of myocardial infarction.
Diabetes mellitus.

Plan: Continue current regimen plus Bayer Aspirin and introduce Lipitor in the evening. Consult a vascular surgeon.

Carotid artery stenosis is basically just a narrowing of the artery... which is exactly what your grandmother is dealing with right now. It’s usually driven by things like smoking, high blood pressure, or diabetes...
The scary part is that this kind of blockage can trigger anything from minor ischemic strokes to major ones, or even death...
Back in the day, the standard move was surgery—an endarterectomy—but nowadays they mostly go the route of placing an endovascular stent. I’ll be honest, I don't know the nitty-gritty details of how that specific procedure works... maybe Scott Allen10 could weigh in on that...
But look, as much as it hurts to say this, I think everyone else is right. A life lived to 91? That's a hell of a run. No matter how many ways there are to "fix" the stenosis, you can't ignore the fact that the body just isn't built the way it used to be. Other issues are already starting to surface... we're looking at blood sugar problems, angina, and stroke risks...
Doctors generally won't even touch this procedure if a patient's life expectancy is under two years, or if they have an irregular heartbeat, a total blockage, or an allergy to the meds used during the process.
Sometimes... you just have to let go. It might be better to just let your grandmother spend these final days surrounded by the people she loves...