Every subway station in the residential areas has bike racks, so a lot of people ride their bikes to the stations, lock up, and then walk at their destination.

I never bothered to buy a bike when I was over there, so I had to walk everywhere... otoh, I did lose a lot of weight (which I promptly gained back once I got addicted to regular sodas).

I think you can bring folding bikes on subways... and if it's an extra-light road bike, they might let you carry it if you keep it off the ground the whole time, and as long as the subway isn't packed. But it probably depends on how anal the station staff are... just tell him to walk through the turnstile with it over his shoulders and see what they say