So he mailed it regular mail? I very recently had a tracked chip "delivered" on Saturday that did not show up in reality until the following Thursday (and then only after opening an investigation with USPS). If it is not tracked, you are just going to have to hope for the best.
The USPS is pretty screwed up right now. I have something coming from near Houston to Sarasota, 800 miles. So far, in six days, tracking shows it's made it to Denver -- 830 miles further away. It might be on a trip around the world...