If your parents are over 70, keep it simple. …
If they’re over 80, it could get even worse. Hopefully, for you, it won’t.
Worse, Go Go Quincy extends it down to those age 55 or over. Sheesh!
Let's avoid stereotyping the “elderly”. Their skills vary greatly. I know people over 70 who are astrophysicists, computer scientists, data analysts, engineers, professors, authors, etc. They are incredibly technically proficient.
I also know other people over 70 who aren't in science or tech-related fields, yet who are are quite competent with technology and computers — after all, many people aged 70+ today, have been using Macs for 40 years! Starting in their 30s or 40s, they've been through a sea change of devices, peripherals, OSs, accessories, hard drive types and connections, etc. and handled them with aplomb.
I also know several “youngsters” in their 20s and 30s who are so used to their self contained iPhones or iPads who could no more handle what the OP is proposing than work a digital camera or a VCR. If anything, many of those aged 70-90+ are far more capable of handling different set ups!
Age is not the differentiator, even if we know some older people to whom the difficulties apply.
I particularly cringe when people use “grandmothers” as the archetype of the tech-challenged. For one thing, many grandmothers are well under 70 and, for another, many, no matter their age, are technically talented professionals and skilled computer users.
It'd be far more accurate for us to refer to the people we have in mind as the “less technically savvy” or those “don't have the patience for puttering with their tech gear” or who “want an easy-to-use tool not a tech project!”! 😁
I've known people of a range of ages who fall into each of those categories.
In any case, the OP needs to take the advice here to heart and see whether it applies to their parents in particular. That is, judge their parents' skill level by what they've seen and experienced of their abilities, not assume something about them based on their age!