What is the treatment for Pneumonia?

A friend of mine has Pneumonia and was hospitalized for it. Upon his release the gave him a prescription for moxifloxacin. (3 pills one daily-400 Mg's) and prescription for Prednisone. (20mgs each -10 pills) with proper instructions on how to take them. He is missing the last two tablets (he only was given 8), is this going to make a difference. while he was in the hospital, we was given these in iv form. I don't understand the application of prednisone for this disease, if it suppress the immune system.Shouldn't the Moxifloxacin, been a longer prescription then just 3 tablets? He also had the flu and pneumonia shots while in the hospital. He was in the hospital 2 1/2 days.