I have made it a point not to pester him or sound like I'm nagging, so I only bring it up occasionally in friendly conversation. Every time I mention it, he says "I should get a bike".

I probably would have quit mentioning it years ago, but his worsening health and the fact that he has memory lapses makes me think it's probably a good idea to gently bring it up now and then.

I thought it would be a good idea to give another good reason for my cycling enthusiasm after what happened in my San Francisco steep climb thread. A couple posters in there wondered if all I did was take long solo rides and climb hills, which makes me think I'm giving people in here the wrong impression of me. I do have other interests, but I never thought it necessary to bring them up in a cycling forum.

Depression is a definite possibility. It can be so overwhelming that even moderate exercise won't make you feel better. I was riding around last night thinking about the friend in my OP and another friend who is morbidly obese and won't ride right now because "it's too cold". I am worried about losing both friends to an early death due to health problems. Unlike most rides, this one didn't make me feel better as time went on, so I went home.

Living near some hills would sure help, as maybe intense exercise helps the mood better than moderate exercise.