Have you asked him what would be most helpful? Would a cleaning lady, meals on wheels or such ancillary services help take some of the exertion off leaving him with more energy (and breath) to try and do the things he enjoys in small doses? What about looking into the RSVP program? http://www.seniorcorps.org/
This program helps connect able body seniors with volunteer opportunities in their area. It is also a chance for him to learn a new skill and meet some other folks, encouraging a social aspect may help him develop new passions.