I would suggest Joint Regeneration may help in addition to the great suggestions in gpo’s stack.
It works towards regeneration of connective tissues via the fat to stem cells concept. It has helped me a lot with high blood pressure issues, and it’s possible it may help your friend as well.
Something interesting that isn’t always common knowledge is that blood vessels are comprised of connective tissue, and things which help improve the health of connective tissue (e.g. collagen, hyaluronic acid) are generally very helpful for the health of blood vessels.