An Urgent Care Doctor Prescribed My 2 1/2 Year Old

An urgent care doctor prescribed my 2 1/2 year old grandson 4.5 ml prednisone once a day for 5 days. He has a start of pneumonia and was also prescribed 7.5 ml twice daily of amoxicillin. He has a hoarse voice and allergies and was already giving him zyrtec. I'm concerned giving him the prednisone and haven't yet and I feel the amoxicillin will help him alone. Am I right?