I quit carrying frangible rounds ... Glaser Blue in the older "flat" nose cap configuration, and then Blue & Silver in the "round" nose versions, and any of the MagSafe loads ... many years ago. At first it was a deliberate decision on my part, and then in later years it was prohibited by agency policy.
While you DO have a very valid concern for the safety of anyone else "downrange", the use of specialty ammunition might not be the exact answer to your problem, and might very well introduce a different problem ... Your call, so to speak, and you're right to start looking for as much information as you can find so you can hopefully make an informed decison ...
I think it was sometime after a local PD experienced a "failure-to-stop" problem many years ago, while one of their officers was using a popular frangible round, that our agency stopped authorizing the use of frangible ammunition in service weapons, and nowadays they aren't even premitted in off duty weapons.
If I remember right, I think the situation involved an armed suspect who sustained a close range hit by a Glaser round, in his neck, and he wasn't exactly what you'd call "incapacitated" ...
Sure, I remember when the local gunstore/distributor of Glaser ammunition showed me "secret" X-ray photocopies he'd received, in hushed tones, showing the awesome & frightening wounding capability of the then-current Glaser rounds ...
The MagSafe rounds included some very interesting variations of frangible bullet composition, but some of the more interesting ones either weren't produced in much quantity, or else weren't commonly offered to the general public. I think I still have some .44 Magnum MagSafe loads somewhere in my ammunition cabinet. I've been tempted periodically to use them for gopher eradication out in the orchard.
If you visit Glock Talk, and send a PM to ULVER ... as I recall, he used to know Joe, the developer of MagSafe, in the early days of the product ... he might be able to offer some informed opinions and personal experiences about the use of different MagSafe loads.
In the meantime, remember to know your downrange "background", regardless of the ammunition you select ...
Sometimes circumstances exist that might make the use of a firearm inappropriate, even if the threat of immediate serious bodily injury or death might otherwise make the use of deadly force in a defensive capacity seem reasonable and justified.
Cops have to consider such things each and every time they draw and present their service weapons, and so do civilians ...
I can't offer anyone legal advice, and won't even pretend to infer that I can ... I'm not an attorney and I don't practice law. Period.
But anyone who considers it likely that they might have need to use a firearm (or any other form of deadly force, for that matter) for defensive purposes should certainly learn as much as possible about the laws governing the use of deadly force for defense of self (or any known/unknown third person), even it means spending money asking for the opinion of an attorney familiar with such areas of the law.
In many states CCW classes require the permit holder receive at least a basic awareness and knowledge of the applicable laws. This is generally the eye-opening part of theCCW classes I assist in teaching. It's the rare class where at least one of the folks attending isn't surprised by the amount of responsibility that's placed upon them, under the law, regarding the use of deadly force. The part of the classroom lecture about how bare fear, alone, is NOT sufficient to justify the use of deadly force, etc., etc., is especially a surprise to a lot of folks, for some reason.
If you know any local cops that you can ask about such things, that's fine ... just remember a couple of things, though ...
Six cops might give you a total of seven different opinions about how they MIGHT perceive and enforce different laws ... and that while cops may the first folks that respond to investigate a shooting situation, the prosecuting city attorney, district attorney, grand jury or what-have-you will often be making the decision of whether or not to prosecute ... and then there's the entire civil litigation potential, wrongful death, emotional pain & suffering of the suspect's surviving family members, etc. ... not to mention potential civil rights issues.
Even a "righteous" self defense shooting can cost thousands of dollars in legal fees, and impose horrific emotional cost on the people involved.
Owning a firearm and the "best" ammunition is easy ...
Nobody in their right mind ever desires to be involved in such a situation, however ... and I'm certainly not implying that anyone here does ... but it's always a good idea to take a moment and remember to think beyond the firearm & caliber issue, no matter how much we might enjoying friendly discussion on these forums.
Hey, I didn't mean to imply that you weren't aware of these issues. Obviously, you're asking about ammunition that minimizes the risk to your parents, after all.
It's just that we're talking about the potential use of deadly force, after all, right?
Sorry, I didn't mean to become pedantic or block the sidewalk with my soapbox, or anything. Honest.
Someone might make some money offering a "fastbolt" filter around here ...
Unless you have trouble falling asleep, and need something to put you under ...
Think, plan and stay safe ...