Has he been seen by his local respiratory physiotherapist? Can give advice on exercise, relaxed breathing techniques and energy conservation, and generally improve quality of life. Often it is the fear of becoming breathless that stops people moving. Ask G.P. to refer him to this service if he hasn't already seen them (physio can do home visit if necessary)
I think first of all you should consider your doctor and ask if he is able to have a little walk or not. Secondly, try to keep him busy in his bed. Give him TV and a lap top with internet. This will keep him in touch with the outer world. However, don't try to stretch the patient beyond doctor's advice.