Good for your mom. My MIL is 72 and there's no way she would be able to pack in a carry on. Even for a weekend trip to come visit us she brings the larger suitcase plus carry on plus her purse plus a canvas bag where she puts her airplane pillow, water bottle, headphones, and whatever knickknacks she grabbed on her way out the door
I still don't know how she's able to get away with essentially 2 personal items on the planes. She does it all the time. I guess the gate agents see her on a wheelchair and decide to let it slide