How can I help my grandma prevent further memory loss?

Caring for grandma. That's nice of you to want to help your grandma. If she hasn't been evaluated yet by her doctor, that might be a good place to start. There are so many reasons for memory problems. Her doctor can evaluate what's going on and take it from there. Often memory problems can be improved, but it helps to be evaluated by a professional. Keep in mind that nobody's memory is perfect.