Under doctor's care and recommendations, I would try to change to a healthy diet and exercise. First start any exercise program slowly. It's a lifestyle change. Exercise does a great job of reducing stress and making a person relax. It's a "wonder drug".
There are herbs that help with anxiety and well-being, but I would start with a sound diet and exercise program first. Again, I would suggest this under doctor's care, particularly with anyone that has high blood pressure or other health concerns.
Years ago, I found that weight training made me so sleepy that I slept so deeply. I was really surprised. I figured that only a cardio-vascular workout would only do that. But lifting weights can really make one so relaxed. I must caution again, although, people with high blood pressure have to be very careful with lifting weights. This should be accomplished very slowly as the body is returning to health.
For people that don't normally exercise, a walking program, is a nice step in the right direction....