Mobility or memory issues may make you question your mom's ability to care for a dog. Don't ignore your concerns. If she can't care for a dog, the dog would be the one paying for the lack of proper care. It can lead to an unruly/untrained dog or an unhappy dog. Instead, consider these alternative options.
Talk to Her About a Cat Instead
See if your mom would be willing to have a cat instead. While a cat still needs care, products like self-cleaning litter boxes, automatic food dispensers, and water fountains make that care easier to manage.