Amiodarone can cause interstitial lung disease, most notably interstitial fibrosis. It is possible, therefore that the drug can cause or, as you say, "expedite the progression of the fibrosis." As to your question, “should this drug have been given to him considering the COPD”, you must discuss with your father’s physicians. Also consider these additional questions with your father’s physicians: Were there equally effective, less dangerous drugs that might have been used? and was the risk benefit ratio, in this circumstance, favorable? As for your question “should the drug be discontinued?” you must discuss the potential consequences of that action vs. the need to control cardiac arrhythmias. Finally it is true that the drug and/or the effects it has set in motion may remain in the system for some time after it is discontinued.
You don't say how long he has been taking the Amiodarone. I think he would need to be on it for a while before a pulmonary fibrosis could develop from the drug. Plus I think it is quite a rare side effect. Maybe they saw evidence of it on prior tests but didn't mention it.. Yes, it is true that the drug stays on board for months after it is dc'ed. I am not a physician, but I would think that they should stop the drug.