Don't panic, yet! I am a surgical nurse and I can tell you from experience that sometimes they are not urgent. Depending on (excuse the wording) what is stuck in there and how easily they can stick it back in, they may or may not be able to delay surgery. My friend's son had one and they were able to delay it for six months. They just taught her what to do when that happened by reducing it (or "stuffing it back in" lol). Others do need to be done right away, but if it was dangerously urgent, they would have had you in to see a surgeon sooner than Friday (i.e. the ER that night).
More than likely he has had it for a while and you just didn't know it, unless he had an injury that caused it recently.
Relax until Friday and see what they say about it, before you worry yourself into labor! ;) The surgery is done on an outpatient basis and easy to recover from.