It seems to me that the benchmark for whether or not a "weak" or "feeble" elderly person should or should not carry as more to do with their mental capacity than their physical abilities. Would you recommend that a disabled younger adult in a wheelchair, for example, not carry due to the risk of the weapon being "taken" from him by any "self respecting" thug? Of course not.
Those without sufficiently capable judgment to determine the appropriateness of the use of force in defensive situations should not carry and must rely other resources for protection. Age has nothing to do with that, nor does physical limitations, within reason. Everyone has the right to defend their lives with lethal force if necessary....as the lives of others are as valuable to them as ours is to us.
Back to point, it is simply a matter of trying a number of options until one emerges as a good fit. And then there is the practice and the education and the committment to acting responsibly....same as for the rest of us.
