Their Fire Chief or Captain ought to be contacted. I can understand an EMT’s concern for his patients safety but a simple, “Sir, have you been drinking?” could have sufficed at the scene. Without any real proof - breathalizer or some other test, he hasn’t a leg to stand on. You can bet if you don’t follow up on this it will be in a record file somewhere.
If it is followed up and a record is found that indicates drinking and the record is expunged after some action it will surface again UNexpunged and with a new notation referring to noncooperation and surliness.