Hello,
Since he is on antibiotics and they saw something on x-ray, it sounds like he has
bacterial pneumonia, which, fortunately, is not very contagious.
Viruses, which typically cause colds or the
flu, are much more contagious than bacterial infections, like what your friend has.
While there is still a small chance he could pass it to you, as long as you have a normal immune system, your friend is careful to cover his mouth when he coughs and wash his hands, your risk of getting pneumonia should be very small.
Especially now that he is on antibiotics and is coughing a little, I don't think you need to worry too much about it.
Hope I have answered your query. Let me know if I can assist you further.
Take care
Regards,
Dr Aaron Branch, General & Family Physician