One of the considerations with congestive heart failure is the need for fluid restriction and the patient will need to work her doctor to be able understand how much she should be getting daily.
Sodium restriction is important for bringing down the blood pressure. In the case of this woman, I would employ a DASH diet to bring down her blood pressure with emphasis on plenty of fruits and vegetables as well as dairy products such as yogurt to obtain regular amounts of calcium.
Since being overweight contributes to higher blood pressure, if she is overweight, then the DASH diet should be combined with a weight loss program by restriction of calories.
Regular aerobic exercise can also support healthy blood pressure levels. I'd recommend about 30 minutes three times weekly.
Because of her condition, I'd also recommend supplementation with CoQ10 to support the function of the heart. If she has a low vitamin D status, which is associated with higher blood pressure, then I'd also recommend a vitamin D supplement.