@Paul305 Aspen over Labor Day weekend probably gets booked up pretty full. I think it would be quite rude to wait until a few weeks before this reservation to cancel it. The guest may not be able to find anything else on that short notice that isn't way more expensive.
If there's a posibility that you might cancel it for your mom, cancel it now.
You do know that if you cancel a reservation, Airbnb will block those dates and you won't be able to rebook them, right? So if your mother doesn't take it, it will be empty over Labor Day, unless you book it through another platform.