There's lots of exercise programs out there for the physically impaired! Everyone can exercise, whether they're elderly, in a wheelchair, etc.

Find a book/program/video like: http://www.armchairfitness.com/

I have hand weights I got at the local drugstore I use while I'm watching television. I just "play" around with them (my arm is too "fat" for a large adult blood pressure cuff, they'd need a thigh cuff to measure me correctly and they don't have one so I'm not taking any meds until I get my arm down so it reads right with a large adult cuff) and have a "rubber" ball I squeeze between my knees, I try to wander around my house/up and down my stairs as much as possible each day (think of something to tell my husband who works upstairs (I work downstairs) and go up and tell him rather than shouting up) and try to think of a "chore" like grocery shopping to do out each day. I'm uncomfortable and get out of breath and my asthma kicks in, etc. but I do it anyway, as it won't get any better unless I work at it. I'd rather have pain now than potentially more pain later.