You are most definitely a low life and the company will recognize your disloyalty to your so called friend as exactly that. You are a traitor,spy,snitch and no-one respects you.
Any persons sickness is confidential, did it ever occur to you that he may not be telling you accurate information about his illness as its none of your business. There are numerous reasons why someone may not be fit to fly an a/c. It is against the law to fly if not 100%.
Aviation would be better off without you...