Can Memory Loss Associated With Old Age Be Treated?

In the past month my mother, soon to be 76, is experiencing loss of memory & seems to be very confused. She is not good at drinking water. Her brother has recently went into a nursery home & will be there until he passes. Her sister s health is not good either. She worries, I think constantly , about their situation. Also she is considered clinically blind, star gart, & because of this she has fallen many times. I think she continues to fall far more than she will say. In March & April of this year she had carotid artery surgery. Blockage was in the 80 to 90 percent range causing her to black out & fall. She thinks the surgeries have brought on the memory loss. She has a 6 month appointment coming up for the surgeries she has had. I m wondering if these surgeries could have brought this on? Could it be a vitamin deficiency? She struggles to have conversations & remembering peoples name. People that are close in her life. I m very concerned for her at this point.