Gman

Here is the situation:

My Dad is about 53 years old, 5'4 - 5'6ish, and 180 pounds. He'd like to lose about 20 pounds and get into shape, but he has had elbow and knee surgeries which limit his physical prowness. I mean, he can walk and run and everything, but he says it bothers him if he does it for an extended period of time.

So, my question is what would be some good exercise routines that are not TOO intensive, but intensive enough to allow him to lose some weight?

Thanks for any help in advance!