If this is a case of arteriogenic ED, there are studies that demonstrate that taking a small dose of Viagra, Levitra, or Cialis every night before bed
for several months (not just as needed
for sexual activity) can improve erectile function long after one stops taking the pills. That is the beauty of this: it can still work AFTER you stop taking the pills.
And there's a lot more you can do. Antioxidants such as vitamin E or pomegranate juice can improve blood circulation.