You know your grandmother better than I, so I have little doubt that you may be right. Certainly there are plenty of senior citizens that do not have the physical or and mental abilities to properly wield a weapon. I'd like to think that all of those are well taken care of with others protecting them in one way or another.
I have about a dozen grandmas in my neighborhood that are all physically and mentally doing very well. They don't need walkers or wheelchairs. some still work, some run businesses. They garden, the go out. Every single one of them can wield a shovel or a firearm if need be.
Sadly there is advice out there that puts them in more danger in a similar way that you describe with yours - I've heard popular advice repeated like 'you need a revolver that don't jam' - best thing is 'a double barrel 12 ga shotgun' - quite frankly I think that is terrible advice for most of them.
For many with the kind of physical limitations in our area, something like a GSG-16 .22 , a Mossberg 715 Pistol .22 , even a Walther Arms Uzi Tactical Rifle Semi-Auto .22 - these things would be easier to use, less fear of recoil, easier to keep on target of bad guys and less chance of inuring self, or bystanders / neighbors..
yet some of the GC ideas would limit access to exactly these kinds of safer features all in the name fear mongering 'military assault accessories' -
the grandma next door would be less safe being forced not to have access to these options and instead forced to use something will less control and options.
That's simply truth.
again, it may not be true for every grandma in the world, but a majority of them (that are not bedridden / incapacitated etc), I think so.