@Madeline--Lynn-0 Adult children do sometimes ask to book for their parents, not knowing that third party bookings are against the TOS. They usually do this because the parents aren't tech-savvy and would be intimidated by the whole online booking and communication thing.
But as Ann says, the person requesting this should help their parents set up an account and show them how to navigate things. If then the booking seems fine, you still might want to be a bit more flexible about communicating with non-tech savvy guests by maybe using phone calls, rather than Airbnb messaging with them, more than you otherwise would, just to make things a bit easier on them.
One thing to be aware of with older couples is that they often don't understand what staying at an Airbnb means. They think it's just an alternative to a hotel, and expect daily maid service, daily towel changes, etc. They may also have a hard time figuring out how to use appliances, how to work the TV, etc, so you might have to do a bit more hand-holding than normal, and make sure you clarify things re cleaning, etc. with bookings from elderly couples who are new to Airbnb.