Usps express mail? My friend sent her Dad's medicine that he forgot when he got here. Here is VA from OH?

She paid for overnight. It was suppose to come by noon on Saturday. I called the customer service and each person told me a different story. They put a research on it since its medication, but as of Sunday no word whatsoever and no update on their website. It went to Cleveland OH and shows it went to Chicago IL heading to its destination and thats where it stops. cold. It is a Sunday, and tommorrow is a Holiday, is this the problem? I received no answers from the USPS people except since it didn't reach there you'll get a refund. Is it lost? I am so confused. Thanks