What exercises are recommended for low BP??? HELPPP?

My mother is 40lbs overweight and has really low blood pressure(80/69) .But I really want her to loose the weight, without her blood pressure getting lower,while still loosing weight. I believe the reason her blood pressure is low is because she has lost a lot of blood recently due to menopause. Every time I take her to her doctor, all he says is she's fine. She's always tired as well. ANY SUGGESTIONS??? Thanks in Advance