I need pointers on how to stay in shape with a broken ankle

My dad has become a running machine, losing 50 pounds over the past year or so, and he has hit a bump in the road...literally. My dad was running on a poor quality trail when the dirt crumbled causing him to break his ankle. The doctor says it was such a bad break that he will not be able to run for a year. The doctor suggested swimming or riding a stationary bike. I am really proud of my dad for working so hard to get in the best shape of his adult life and I wanted to know if anyone has any other ideas for exercise that he can pick up to stay in shape. Any pointers?