Fruits and vegetables are not the be-all and end-all (especially fruits, which are more Sugar than anything else). Fibrous vegetables are important, of course (mainly for their antioxidant content), but so is protein and natural fats. Omega-3 fatty acids (from fish oil---NOT flax) would be important. I'd greatly limit sugars, starches and grains. She should also be consuming high quality, preferably free-range, grass fed sources of protein (do NOT be concerned about naturally occurring fat at all) and some fish. Vitamin D deficiency, as I mentioned, is extremely common in older folks and can be a cause of elevated blood pressure. I have yet to see a person's blood chemistry profile (other than my own) that ISN'T deficient in D. Older people have a much worse problem with this. It is a fat soluble nutrient, so low fat diets only help perpetuate the deficiency and slow biliary function.
Magnesium deficiency is also quite common and can perpetuate the blood pressure issue. Chronic stress can depleat this (plus B-complex, and C), so I'd look into some supplementation. I recommend magnesium glycinate.
If you'd like a copy of a recent more detailed summary of dietary suggestions I sent to the group, I can back channel that to you. Just let me know.