My mother has ischemia. is this reversible? how is it typically treated?

Depends: on location. Ischemia means lack of blood supply. It may or may not be reversible depending on location of organ involved and etiology of ischemia.

Definition: ischemia: The term ischemia generally suggests a reduction of the blood supply to a given area of the body such that the functionality of that part of the body is impaired. Could be from a blockage in an artery delivering blood to that part of the body, or could be from a general reduction in blood supply to deliver to that part of the body. Treatment would be dictated by the cause.