I was thinking along the lines of TM's or Janet's posts (before I got to them).
Could you, husband, a friend, etc. invite him to go for a walk, go to the mall, visit a nature center, something that doesn't SEEM to be exercise, but really is? I can walk forever when I'm interested in doing so - sightseeing, window shopping, hiking, etc - but I'd be bored to tears on a treadmill.
