My 65 year old gpa has walking pneumonia. and he has been short of breath for 2 hours what should we do?

See his doctor: Shortness of breath can be expected with pneumonia but you want to make sure that your grandfather is getting enough oxygen and that he isn't developing a complication from his pneumonia. He needs to be evaluated by his physician.

Seek medical help: This is really the kind of question that can not be answered specifically in this sort of forum. An old person with pneumonia can have a lot of complications, including heart failure, pleural effusion ( fluid build up outside the lung) infection with a resistant germ etc...) this question is best handled by his doctor, and always if severe symptoms it is best to call 911/ go to the emergency room.